Integrated intelligent motor protector without external power source

Abstract

The invention discloses an integrated intelligent motor protector without an external power source and belongs to the technical field of motor protection. The motor protector comprises a shell and a control circuit fixed in the shell. The motor protector is characterized in that the shell comprises an outer shell body (1) and a control panel (4) arranged on the front end face of the outer shell body (1). The outer shell body (1) is provided with a power source wire connection terminal used for being connected into a motor power supply loop in series, and a series-connection point is located at the wire outlet end of a main contact in the motor power supply loop. The control panel (4) is provided with a control wire connection terminal used for being connected into a motor starting loop in series, the control wire connection terminal is used for achieving connection and disconnection of the motor starting loop, and a power source wire connection unit and a control wire connection unit are connected to the control circuit at the same time. The integrated intelligent motor protector without the external power source is connected to the wire outlet end of the main contact of the motor power supply circuit in series, connection more conforms to the on-site wire connection habit, and no extra external power source is needed.

Description

technical field [0001] An integrated intelligent motor protector without external power supply belongs to the technical field of motor protection. Background technique [0002] The motor protector is an electrical device that comprehensively protects the motor during operation. In the prior art, before using the motor protector, it is first necessary to set the action parameters of the motor protector through the buttons on the motor protector. After the setting is completed, connect the motor protector to the AC main The operating parameters are monitored. When the operating parameters of the motor are abnormal or reach the preset action parameters, the motor protector will cut off the main power supply circuit of the motor to protect the motor. [0003] At present, the electromagnetic contactor is generally used as the switching device of the motor to be connected in series in the power supply circuit of the motor, and the motor protector is arranged between the contactor...

AI Technical Summary

Problems solved by technology

The set current adopts digital setting and is operated through the buttons on the control panel. Users can modify and set various parameters on site according to the specific conditions of the motor. It is more convenient to use and has a high degree of intelligence. However, the existing intelligent motor protectors generally It adopts a split design and has a large volume, so it cannot be installed uniformly with other electrical components in the control box according to the standard installation method (such as DIN rail installation). Large, the scope of application is limited

[0007] (2) The motor protectors currently on the market are all active types, that is, they generally need to be connected to an external 220V AC power supply when working. Wiring is extremely flawed when wiring on site;

[0008] Although the power supply can also take power from the main power supply circuit of the motor, if it takes power from the downstream of the contactor, the wiring is convenient. However, in the installation stage, in order to ensure that the safety contactor is in a disconnected state, so There is no power supply downstream of the contactor to power the motor protector, and the motor protector cannot be debugged and parameterized; if the power supply of the motor protector is powered from the upstream of the contactor, although it can be Normal power supply, and the debugging of the motor protector can be successfully completed, but this wiring method is more complicated, especially does not conform to the normal wiring habits of electricians, so to a certain extent, it limits the development and promotion of the motor protector

[0009] (3) For the current motor protectors on the market, in order to collect the parameters of the motor during operation, a mutual inductance device (such as a current transformer) needs to be connected in series in the power supply circuit of the motor, and the wiring is more complicated

[0011] In the prior art, when a solid-state contactor is used as a switching device to cooperate with a motor protector, in addition to the above-mentioned various defects, there are also the following defects: because the thyristor generally used in a solid-state contactor As a switching element connected in series in the main circuit, in order to prevent the reverse power supply in the circuit from breaking down the thyristor in the solid-state contactor, a resistance-capacitance protection circuit is generally installed at the output end of the main contact of the solid-state contactor

[0012] In the on-site debugging stage, no-load debugging is generally carried out, that is, when the end of the main circuit is not connected to any load (such as a motor). The control circuit inside the RC protection circuit continuously charges the capacitor in the RC protection circuit. Since there is no load connected to the end of the solid-state contactor, the power supply in the RC protection circuit cannot be released to generate leakage current, so the leakage current is very easy to The commissioning personnel were injured by electricity, causing safety accidents and not conducive to the smooth progress of commissioning

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