84results about "Liquid resistors" patented technology

The invention relates to a solenoid-drive liquid metallic rheostat which is characterized by comprising a casing, paraffin, a copper wire, a communicating vessel, liquid metal and an electromagnetic pump. The casing is filled with the paraffin and the copper wire; the communicating vessel is located on one side of the casing and is connected with one end of the copper wire; the electromagnetic pump is mounted at the bottom of the communicating vessel; and the liquid metal is stored in the communicating vessel, moves up and down under the driving of the electromagnetic pump and is contacted with the copper wire at different height positions, so that the length of the copper wire placed in a circuit is hanged and the variable resistance effect is achieved. The solenoid-drive liquid metallic rheostat takes the copper wire as the main body, utilizes the electromagnetic pump to drive the liquid metal to move to adjust the copper wire resistance, and adopts the paraffin to absorb joule heat, so that the whole system is stable and reliable, small in size, light in weight and low in cost, and can be widely applied to the field of soft starting of motors.

A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

The invention discloses a pneumatic adjustable water resistor. The pneumatic adjustable water resistor comprises a resistor body (3), wherein a through hole which axially penetrates through the resistor body (3) is formed in the resistor body (3); the through hole consists of a small-diameter through hole and a large-diameter through hole which are communicated in sequence; the aperture of the small-diameter through hole is smaller than that of the large-diameter through hole; an electrode A (2) which slides along the small-diameter through hole and is in close fit with the inner wall of the small-diameter through hole is mounted in the small-diameter through hole; an electrode B (4) which slides along the large-diameter through hole and is in close fit with the inner wall of the large-diameter through hole is mounted in the large-diameter through hole; the through hole between the electrode A (2) and the electrode B (4) is filled with an electrolyte solution. The pneumatic adjustable water resistor has the benefits that the quick adjustment of the resistance value of the water resistor is realized; the detachment and the reconfiguration of the water resistor in a high-voltage situation are avoided; the operation is simple; the efficiency is greatly improved.

The invention discloses a brushless automatic control motor liquid resistance starter which belongs to the liquid starter, and aims at providing a brushless automatic control motor liquid resistance starter which not only can continuously and steadily basic constant torque soft starting, but also can repair conveniently. The technical proposal of the invention is a brushless automatic control motor liquid resistance starter comprises a movable electrode plate and a static electrode plate; wherein, the movable electrode plate which is connected with a sealing star of a ring liquid resistance box cavity which is fixedly arranged in a rotating shaft is a circular plate, and a central hole is slippingly arranged on the rotating shaft; a movable contact arranged on one surface of the end of the movable electrode plate is opposite to a static contact on a cover plate of a liquid resistance box which is electrically connected with the post head on the cover plate, and a groove is arranged on the other side of the end of the movable electrode plate; wherein, the groove bottom is a slope which is deep inside and shallow outside, and a slippingly-arranged ball is arranged in the groove; the axially convex bars which are evenly distributed on the circumference of the moving are slippingly arranged in the groove of the inner wall of the liquid resistance box, and a spring is arranged between the end surface of the moving electrode plate provided with the moving contact and the liquid resistance box cover plate. The invention is mainly used for the overloading starting motors.

The invention relates to an adjustable resistance device, in particular to a conducting liquid contact-type friction-free rotary potentiometer. The potentiometer provided by the invention adopts the structure that a ring-shaped conductive electrode (2), a circular arc-shaped naked fixed resistor (3), a conducting liquid drop (4), inert gas and external metallic sealing lead wires (5) are arranged in a ring-shaped gas-tight sealed box (1) in a built-in manner, wherein, two ends of the fixed resistor and the ring-shaped conductive electrode are both led out of the ring-shaped gas-tight sealed box (1) through the external metallic sealing lead wires (5). The rotary potentiometer provided by the invention has the benefits of mechanical contact prevention, friction and noise prevention, long service life, wide application, and the like; and due to the gravity action of the gravitational attraction, the potentiometer can be vertically mounted to be served as tilt sensors, shock sensors, displacement sensors, liquid level sensors, and the like.

The invention discloses a rheostat structure of an electrical-hydraulic rheostat starter. The rheostat structure comprises a water tank, three pairs of electrode bars and an electrode bar lifting structure. The rheostat structure further comprises two locating columns, a buoy and a flexible indication strip, wherein the locating columns are fixed into the water tank; the buoy is arranged on one locating column in a sleeving mode and can move vertically along with the water level; the flexible indication strip is partly inserted in a slot formed in the inner surface of a water tank cover, one end of the flexible indication strip is fixed to the buoy, the flexible indication strip moves vertically along with the buoy, and vertical change of the water level can be converted into horizontal change through the flexible indication strip. The water tank cover is provided with holes which the electrode bars are inserted in, seal rings arranged outside the electrode bars in a sleeving mode and a housing used for fixing the seal rings to the inner surface of the water tank cover. The rheostat structure further comprises a standby water tank, wherein the standby water tank is adjacent to the water tank, a water pump is arranged in the standby water tank, and the water pump can inject water in the standby water tank into the water tank through an inlet in the upper portion of the water tank. The rheostat structure further comprises a magnetic material and a reed switch which are used for controlling the water pump to work. The rheostat structure of the electrical-hydraulic rheostat starter has the advantages of being reasonable in structure, low in cost, easy and convenient to maintain and longer in maintenance period.

The invention relates to an adjustable liquid resistance device, which comprises an electrolyte tank, electrodes and transmission components. The lower ends of the electrodes are arranged in the electrolyte tank, the upper ends of the electrodes are connected with the lower parts of brackets of the transmission components and are provided with a wiring terminal, more than two electrodes are adopted, the upper ends of the electrodes are all connected with the lower parts of the brackets, the upper parts of the brackets are connected with transmission racks, the transmission racks can lift the brackets for 0-1000mm, the electrodes are vertically and uniformly arranged on the brackets, and the spacing between adjacent electrodes is 100-500mm. When in use, the resistance value of the liquid resistance can be adjusted through vertical movement of the brackets or flexible combination of the wiring terminals of the electrodes. The invention not only has a large scope for adjustment of the resistance value, but also can satisfy the requirements of large-scope power adjustment, and ensure the compatible use of high voltage and low voltage, thereby broadening the application scope. In addition, the invention can easily solve the problem of high-voltage insulation.

The invention discloses a liquid metal type ceramic high-voltage variable resistance device, which comprises a ceramic resistance cavity, a liquid metal, a left electrode, a right electrode and a gasmedium. The left electrode and the right electrode are fixed at the left and right ends of the ceramic resistance cavity to form a sealed cavity. The ceramic resistance cavity is composed of a coarsecavity with a larger diameter and a thin cavity with a smaller diameter, which are communicated with each other. The liquid metal is filled in the ceramic resistor cavity, the liquid metal needs to beable to enter the cavity with smaller diameter and conduct the left electrode and the right electrode when the liquid metal is horizontally placed, and the liquid metal cannot fill the ceramic resistor cavity. The gas dielectric fills the remaining ceramic resistor cavity, and the gas dielectric fills the remaining ceramic resistor cavity, and the gas dielectric fills the remaining ceramic resistor cavity must have good insulation characteristics. The device is a variable impedance FCL, which is connected in series in the system circuit. In normal operation, the impedance of the system is very small, but in the event of a fault, the impedance can be rapidly increased without commutation, so that the fault can be limited before reaching the peak.

The invention discloses a fluidic resistor device used for a high-voltage fluidic resistor soft start cabinet. The fluidic resistor device used for the high-voltage fluidic resistor soft start cabinet comprises a cabinet body, wherein the cabinet body is divided into an upper layer and a lower layer by a partition plate; the lower layer of the cabinet body is provided with one or a plurality of fluidic resistor boxes; the upper layer of the cabinet body is provided with a vacuum contactor positioned on the partition plate; a left side and a right side in each fluidic resistor box are each provided with a polar plate; the vacuum contactor is connected with the polar plates in the fluidic resistor box by copper bars; each fluidic resistor box is of a double-layer structure and consists of an inner box body and an outer box body; back-up blocks are arranged between the inner box body and the outer box body; the inner wall of the inner box body is provided with reinforcing ribs; the left upper end of the outer box body is provided with a water inlet valve; and the right lower end of the outer box body is provided with a water outlet valve. In the fluidic resistor device used for the high-voltage fluidic resistor soft start cabinet, which is disclosed by the invention, the size of the cabinet body is reduced, and starting frequencies are increased; since circulating water is adopted for cooling, cooling effects are better, fluidic resistor temperature is slowly raised when an electromotor is started, and the electromotor is frequently started; occupied space is reduced since the size of the cabinet is reduced; and cost is saved.

The invention discloses a water resistor capable of self-cyclically flowing and cooling for industry. The distilled water and other liquid resistor are used as the resistor, so that the resistance liquid can cyclically flow in the system in the premise of not using a water pump by using the effects of the temperature field, the gas pressure and the gravity; the heat produced in the working process is immediately taken away by the resistance liquid and cooled through an external condensation pipe, thereby improving the radiating performance; and meanwhile, since the overall system is an opening system, the resistance liquid is limited by the saturated vapor pressure under the atmosphere, the highest internal temperature of the water resistor is only the boiling point, and the pressure intensity is the environment pressure; the design of the opening system avoids the problem that the water resistor structure cannot be continuously used for a long time since the water resistor structure is damaged by the internal high temperature and high pressured caused by the insufficient radiation in the traditional closed water resistor, the performance of the service life of the water resistor are guaranteed, and the normal operation of the high-power pulse equipment under high-frequency and long-time condition is guaranteed.

The invention provides a liquid metal rheostat. The liquid metal rheostat comprises a liquid container and a pipeline which are used for containing liquid metal and are communicated with each other, wherein the pipeline is internally provided with a moving joint which stretches outside the pipeline, is connected with an external guide line and has electrical conductivity; one end, which is positioned in the pipeline, of the moving joint is connected with a pushing device which has the same shape of the inner end surface of the pipeline and is in tight movable fit with the pipeline; a fixing joint which is used for connecting the external guide line is arranged on the tail end of the liquid container. The liquid metal rheostat provided by the invention is simple in structure and convenient in regulation and is capable of realizing electrodeless continuous change of a resistance value.

The invention discloses a screw drive electrode adjustable water resistor which comprises a resistor body. The inner side wall of the resistor body is provided with a group of sliding grooves, a movable electrode plate is installed in the sliding grooves, and an adjusting screw is installed on an output electrode sealing plate and is in matched connection with the movable electrode plate through threads. When rotating, the adjusting screw drives the movable electrode plate to move in the axial direction of the resistor body in the sliding grooves, and the movable electrode plate penetrates the output electrode sealing plate through spiral guiding. According to the screw drive electrode adjustable water resistor, the correction can be performed by adjusting the distance between electrodes of the water resistor, so that a good resistance state is maintained; compared with the prior art, the motion of repeatedly replacing an electrolyte solution is avoided, and the use cost is also reduced.

The invention discloses a high pressure water resistor which comprises a working water tank made from an insulating material. A phase potential polar plate and a zero level polar plate are concentrically arranged in the working water tank; a resistance value adjusting mechanism is arranged between the phase potential polar plate and the zero level polar plate; a water through window communicating the phase potential polar plate and the zero level polar plate is arranged on the resistance value adjusting mechanism; the resistance value adjusting mechanism adjusts the cross section, communicated by water, between the two polar plates by adjusting the size of the water through window; the cross section, communicated by water, between the two polar plates changes, so that the resistance between the polar plates changes. The resistance value adjusting mechanism is small in inertia and high in control sensitivity, effectively solves the problem of large fluctuation of a load power of a unit, is high in testing precision, good in safety performance and suitable for high pressure environments, can be applied to a direct current test, an alternating current test and a three-phase alternating current test, and is convenient and rapid, low in testing cost, reasonable in structure, convenient to operate and good in universality.

The invention relates to a low-melting-point metal liquid rheostat. The low-melting-point metal liquid rheostat comprises a casing, a static electrode plate, a moving electrode plate, low-melting-point metal, and a screw, wherein the static electrode plate is fixed on the casing; the casing is filled with the low-melting-point metal; the moving electrode plate and the static electrode plate (2) are arranged in pairs; and the moving electrode plate is connected with the screw (5). The moving electrode plate can be driven by the screw to move up and down in the casing so as to change the distance between the static electrode plate and the moving electrode plate and further to change the resistance of the rheostat, thereby achieving the aims of start current regulation and motor soft start. The rheostat system is safer and more stable by using the low-melting-point metal which has the characteristics of high stability, non-toxicity and good thermal and electric conductivity; and the size and the weight of the system are reduced greatly. The low-melting-point metal liquid rheostat provided by the invention can be widely used in the soft start application fields of all kinds of high-voltage and low-voltage large power motors.

The invention discloses an electrohydraulic box used for a high pressure hydraulic resistance which is composed of a liquid storage box for holding the electrolyte, a fixed polar plate arranged in a box body and a dynamic polar plate; the invention is characterized in that the liquid storage box is internally provided with a plurality of cooling ventilating tubes that penetrate the upper box body and the lower box body; a shell which is preserved with a clearance and provided with an air inlet at the bottom part is sheathed on the periphery of the box body; an isolating supporter is arranged between the box body and the shell; the liquid storage box is made of a glass material; the box body for holding the electrolyte is designed to be a structure mode which is provided with the cooling ventilating tubes, and a shell body is additionally arranged outside the box body, therefore, not only the original use functions of the box body are maintained, but also the size of the box body is reduced, thus being capable of greatly reducing the size of the box body for holding the electrolyte and the use amount of the electrolyte; simultaneously conditions are created for the miniaturization of a soft start device of a whole set of high pressure AC electromotor.

A linear dynamic resistor with gradually-increased resistance values is characterized by comprising an insulating container (G11), conductive liquid (G31), an entity (G21), a bottom electrode (G51), a winding rod (R10), a resistance coil (R1), an electromagnetic coil (G41), a controlled access first node (O+), a controlled access second node (O-), a control terminal first node (P+) and a control terminal second node (P-); the linear dynamic resistor further comprises a bridge-type rectifier circuit (G60). An electronic circuit is provided with the dynamic resistor. An electric system is provided with the dynamic resistor. The service life of contactors is long, the manufacturing cost is low, and the linear dynamic resistor is good in isolation and can be applied to high-power circuits, such as a weak-current power circuit, a power circuit and an ultra-high voltage power circuit.

The invention is designed for solving the problem of which the liquid resistor currently used in the squirrel cage motor always carries high voltage so as to threaten the human safety. It comprises a cabinet, a liquid resistor tank located on the moving pole plate and the fixed pole plate, a driver mechanism for driving the pole plates to make up and down movement, and a cooling system. The liquid resistor tank is separated by a stick up plate into a liquid resistor chamber and a slack flow chamber. On the upper portion of the liquid resistor chamber, there is a filter layer, and on the upper portion of the slack flow chamber, there is an oil-water separator; the water outlet is connected to the liquid resistor chamber; the oil outlet is connected to the slack flow chamber. The input pipe and outlet pipe all are made of high pressure resistance materials, and are respectively connected to the entrance and the exit of cooling agent. The cooling system uses high pressure resistance cooling agent.

A variable resistor is characterized in that the variable resistor is mainly composed of an insulating container, a first electrode, a second electrode, a conductor, a resistance liquid, a buoyancy body, a spring and a rotating shaft. The shape of the insulated container is circular; Central part of that insulate container is provided with a hole column. The hole column in the center of the insulating container is fixedly connected with the rotating shaft; at that cent of the conductor, a circular hole is arranged, and the conductor is slidably sleeve on the hole post at the center of the insulating container; a spring is arranged between the conductor and the insulating container. The conductor and the buoyant body together form a floating conductor. The spring forms the elastic mechanical connection between the insulated container and the floating conductor. A first electrode and a second electrode penetrate through the bottom of the insulating container and intervene in the chamberof the insulating container. A motor starter having a variable resistor as described above. The invention has the advantages of simple structure, long service life and low cost.

The invention relates to a resistance-adjustable high-pressure water resistance device. The device comprises a water resistor, a water circulation mechanism for adjusting conductivity and an insulating tube, and the water inlet and the water outlet of the water circulation mechanism are respectively connected with two ends of the water resistor through the insulating tube to form a circulation path; during use, the insulating tube and the water resistor are at high potential, and the water circulation mechanism is at ground potential; the length of the insulating tube meets the formula that Lis larger than or equal to 1.5(2.8U-0.26U2+1.35U3), and L is the length of the insulating tube with the unit being m; U is the peak voltage of the connection point of the insulating tube and the waterresistance electrode, and the unit is MV. According to the device, the water resistor can be flexibly and conveniently applied to various high-voltage occasions, resistors of various voltage classesand resistance values can be provided for a laboratory, the purchasing cost input of the laboratory resistor is greatly reduced, the space utilization rate of the laboratory is increased, and the problems of poor stability and precision of the resistance value caused by long-time continuous high voltage are effectively solved.

The invention provides a direct current adjustable liquid resistance device with a water adding device. The device comprises a cabinet body, an electrode plate, the water adding device and a liquid level detection mechanism, wherein the cabinet body consists of an electrohydraulic case body and an outlet pipe; the electrode plate consists of a fixed polar plate positioned in the electrohydraulic case body, a movable polar plate and an insulating sleeve, the insulating sleeve is wrapped on the partial vertical surface of the fixed polar plate, and the movable polar plate is positioned above the fixed polar plate; the water adding device consists of a throttle valve, an insulating water pipe and an electric controlled water valve; the insulating water pipe is connected in series with the electrohydraulic case body, the electric controlled water valve and the throttle valve sequentially; and the liquid level detection mechanism consists of a liquid level detection alarm device and a floater, and the upper part of the floater is positioned in the liquid level detection alarm device. The direct current adjustable liquid resistance device with the water adding device can be widely applied to high-voltage electrical equipment, can replace a metal electric resistance wire at the direct current end of power electronic equipment, is provided with the liquid level detection mechanism which can detect the water level of electric resistance fluid, can automatically add water into the electrohydraulic case body, and replenish the electric resistance fluid, so that the production process is simplified.

The invention relates to a linear dynamic resistor with gradually increased resistance value. The linear dynamic resistor is characterized by comprising an insulated container (G11), a conducting liquid (G31), a substance (G21), a bottom electrode (G51), an electrode bar (R50), a resistance layer (R51), an electromagnetic coil (G41), a first controlled path node (O+), a second controlled path node (O-), a first control end node (P+) and a second control end node (P-); and the linear dynamic resistor also comprises a bridge rectifier circuit (G60). A motor start-up buffer comprises the dynamic resistor. An electric power system comprises the dynamic resistor. The motor start-up buffer comprises the dynamic resistor. The electric power system comprises the dynamic resistor. The linear dynamic resistor is long in contactor service life, low in cost, good in isolation, and can be applied to high-power circuits such as weak current power circuits, electric power circuits and ultrahigh tension electric power circuits.

A hydraulic driving rheostat comprises a thin tube. A resistor stripe, a mercury column and medium liquid are arranged in the thin tube, the mercury column is arranged in the middle of the resistor stripe, the medium liquid is arranged on two sides of the mercury column, a first piston is arranged at one end of the thin tube, a second piston is arranged at the other end of the thin tube, the first piston and the second piston change the thin tube into a closed hydraulic transmission device, the resistor stripe is communicated with the exterior of the thin tube, and changes of resistance valves at two ends of the resistor stripe are formed by measuring movement of the mercury column on the resistor stripe to cause short circuit of mercury on different portions of a resistor to reflect change situations of the first piston and the second piston. The hydraulic driving rheostat has the advantages of being high in flexibility and low in cost of construction.

A variable resistor is characterized by mainly comprising a containing cavity, at least two electrodes, resistance liquid, and a floating conductor. A variable resistor is characterized by mainly comprising a containing cavity, at least two electrodes, resistance liquid, a floating conductor, and an easily deformable wire. A variable resistor cluster is formed by arraying the variable resistors. A variable resistor cluster is formed by coaxially connecting the variable resistors in series. A motor starter is formed by reasonably connecting the variable resistors or the variable resistor clusters with a motor according to needs. The variable resistors, the variable resistor clusters and the motor starter have the advantages of simple structure, long service life and low cost.

The invention discloses a rheostat structure of an electrical-hydraulic rheostat starter. The rheostat structure comprises a water tank, three pairs of electrode bars and an electrode bar lifting structure. The rheostat structure further comprises two locating columns, a buoy and a flexible indication strip, wherein the locating columns are fixed into the water tank; the buoy is arranged on one locating column in a sleeving mode and can move vertically along with the water level; the flexible indication strip is partly inserted in a slot formed in the inner surface of a water tank cover, one end of the flexible indication strip is fixed to the buoy, the flexible indication strip moves vertically along with the buoy, and vertical change of the water level can be converted into horizontal change through the flexible indication strip. The water tank cover is provided with holes which the electrode bars are inserted in, seal rings arranged outside the electrode bars in a sleeving mode and a housing used for fixing the seal rings to the inner surface of the water tank cover. The rheostat structure further comprises a standby water tank, wherein the standby water tank is adjacent to the water tank, a water pump is arranged in the standby water tank, and the water pump can inject water in the standby water tank into the water tank through an inlet in the upper portion of the water tank. The rheostat structure further comprises a magnetic material and a reed switch which are used for controlling the water pump to work. The rheostat structure of the electrical-hydraulic rheostat starter has the advantages of being reasonable in structure, low in cost, easy and convenient to maintain and longer in maintenance period.

A variable resistor is characterized by mainly comprising a containing cavity, at least two electrodes, resistance liquid, and a floating conductor. A variable resistor is characterized by mainly comprising a containing cavity, at least two electrodes, resistance liquid, a floating conductor, and an easily deformable wire. A variable resistor cluster is formed by arraying the variable resistors. A variable resistor cluster is formed by coaxially connecting the variable resistors in series. A motor starter is formed by reasonably connecting the variable resistors or the variable resistor clusters with a motor according to needs. The variable resistors, the variable resistor clusters and the motor starter have the advantages of simple structure, long service life and low cost.

The invention relates to a high-frequency non-inductive resistor, which comprises a resistor shell body, columnar electrodes, a circulating pump, a water tank and a temperature sensor, wherein the resistor shell body is used for containing saline water, and the columnar electrodes are arranged on the left and right side walls of the resistor shell body. The water tank is used for containing saline water and is positioned above the resistor shell body. A water inlet in the left side wall of the resistor shell body is communicated with the bottom of the water tank through a water inlet pipe, and a water outlet in the right side wall of the resistor shell body is communicated with the upper part of the water tank through a water outlet pipe provided with the circulating pump. The temperature sensor is installed on the water outlet pipe at the water outlet in the right side wall of the resistor shell body. The high-frequency non-inductive resistor has the following advantages that: (1) the high-frequency non-inductive resistor hardly generates distributed inductance and distributed capacitance, and is suitable for loading testing of high-frequency equipment with various powers; (2) and as the circulating pump is adopted to circulate and cool the saline water in the resistor shell body, the resistor is suitable for the loading testing of large-power high-frequency equipment, such as the loading testing of a transmitter of more than 50 kW (13MHz).

The invention comprises liquid tank, pole plate and contactor. The lower portion of the liquid tank has a separator used for separating the tank into an upper chamber and a lower chamber; the self-priming pump is located in the lower chamber; between the upper chamber and the outlet of the self-priming pump there is a communicating pipe; three pole plates in the upper chamber are respectively connected to the three phases, wherein the pole pale at middle portion is a stick up plate, and the two plates at both sides are sketch plates whose upper portion and lower portion shape the stick up plate; the distance between the lower portion of the side pole plate and the middle pole plate is more the one between the upper portion of the side pole plate and the middle pole plate; there is a slopping plate between the lower end of upper stick up plate and the upper end of the lower stick up plate.

The invention discloses a resistance changing structure for an electro-hydraulic starter rheostat. The resistance changing structure for the electro-hydraulic starter rheostat comprises a water tank, three pairs of electrode bars and an electrode bar lifting structure. The electrode bar lifting structure comprises a screw rod, a nut and a belt pulley, wherein the nut is matched with the screw rod, and the belt pulley is mounted on the screw rod and is in linkage with a motor. The motor rotates and drives one of each pair of electrode bars to move up and down. An oil cavity containing oil is formed in the top of the screw rod, and an oil hole communicated with the oil cavity is formed in the upper portion of the screw rod. The resistance changing structure for the electro-hydraulic starter rheostat further comprises an oscillating rod, one end of the oscillating rod is hinged to the screw rod, and a sealing block is arranged at the other end of the oscillating rod. The oscillating rod falls naturally under the action of gravity. The sealing block can seal the oil hole. When the screw rod rotates, the oscillating rod opens the oil hole under the action of centrifugal force for releasing oil, and the screw rod and the nut are lubricated. The resistance changing structure for the electro-hydraulic starter rheostat further comprises a standby water tank, an automatic water charging system and a sealing system preventing water from losing. The resistance changing structure for the electro-hydraulic starter rheostat has the advantages that lubricating oil is added automatically through a rotating mechanism, water is added automatically, water loss is prevented, maintenance is easy and convenient to carry out, and a maintenance period is prolonged.

The invention discloses a rotating liquid variable resistor which mainly comprises a containing cavity, at least two electrodes, conducting liquid and at least one resistor body. The invention discloses a rotating liquid variable resistor cluster which is formed by an array of the rotating liquid variable resistors which are coaxially connected in series. The invention discloses a motor starter which is formed in a manner that the rotating liquid variable resistors or the rotating liquid variable resistor cluster are selected as required and are reasonably connected with a motor. The rotating liquid variable resistor, the rotating liquid variable resistor cluster and the motor starter are simple in structure, long in service life and low in cost.