Stall test device for electric motor
By designing a motor stall test device that includes a transformer and an arm, the problem of low efficiency in existing motor stall test devices is solved. This device enables the detection of stall characteristics in both forward and reverse rotation of the motor, thus improving detection efficiency and accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU XINGYU ELECTRIC MASCH CO LTD
- Filing Date
- 2025-07-04
- Publication Date
- 2026-07-10
AI Technical Summary
Existing motor stall test devices are inefficient in motor factory inspections and cannot efficiently detect stall current, stall loss, and stall torque.
A motor stall test device was designed, comprising a transformer, a base, a vertical support, and an arm. The transformer reduces the voltage of the motor, and the arm and vertical support act as a stall mechanism when the motor rotates in both directions. Combined with an ammeter to record the current indication, the operation process is simplified.
This technology enables effective detection of stall characteristics regardless of whether the motor is rotating forward or backward, improving testing efficiency, simplifying the operation process, and ensuring the high efficiency and accuracy of motor quality testing.
Smart Images
Figure CN224480552U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a stall test device for an electric motor. Background Technology
[0002] A locked-rotor test setup typically includes an autotransformer, a hydraulic dynamometer connected to the motor shaft, and electrical testing instruments. It measures the motor's locked-rotor current, locked-rotor losses, and locked-rotor torque, obtaining the data needed to plot a pie chart of locked-rotor characteristics. During use, the motor must rotate forward. If it rotates backward, adjust the motor's wiring. Then, adjust the hydraulic dynamometer to gradually increase the motor's load torque until the motor stops rotating. At this point, the electrical testing instruments record the motor's locked-rotor current, locked-rotor losses, and locked-rotor torque. This type of locked-rotor test setup is suitable for motor trial production testing; its efficiency is too low for factory inspection (i.e., unit-by-unit inspection). Utility Model Content
[0003] In order to improve the efficiency of stall testing and ensure product quality, this utility model designs a stall testing device for electric motors.
[0004] The technical solution of this utility model is a stall test device for an electric motor, which includes a transformer BK, a base 3 for placing an electric motor 4, an arm 2 sleeved on the rotating shaft 6 of the electric motor, vertical supports 1 connected vertically on the left and right sides of the base, the arm being located above the vertical supports, and either end of the arm can rest on the vertical supports. The upper part of the arm is provided with a slot, and a key 8 is inserted into the slot, which can extend into the keyway 7 on the rotating shaft. The output terminal of the electric motor winding is connected to the secondary winding of the transformer BK, and an ammeter A is connected in series between the secondary winding of the transformer BK and the output terminal of the electric motor winding. The primary winding of the transformer is connected to the mains power, and the secondary voltage of the transformer is about one-quarter of the mains voltage.
[0005] The method of use is to place the motor on the base, put the sleeve on the motor shaft, rotate the motor shaft so that the keyway on the shaft is aligned with the slot on the sleeve, insert the key into the slot and extend it into the keyway on the shaft, turn on the power, the arm and the vertical block will block the motor, record the current (blocked rotation) indication of the ammeter, then turn off the power to the motor and remove the sleeve.
[0006] The beneficial effects of this utility model are that, regardless of whether the motor is rotating forward or backward, the arm and the vertical block can block the motor. The operation process is simple, the testing efficiency is high, and it has high practicality for the inspection of each motor, effectively preventing unqualified products from leaving the factory. Attached Figure Description
[0007] Figure 1 This is a schematic diagram of the structure of this utility model.
[0008] Figure 2 for Figure 1 Top view.
[0009] Figure 3 For testing electrical wiring diagrams.
[0010] Attached diagram labels: 1-Vertical support, 2-Arm body, 3-Base, 4-Motor, 5-Sleeve, 6-Shaft, 7-Keyway, 8-Key body, 9-Pad, 10-Spring, 11-Blind hole. Detailed Implementation
[0011] A stall test device for an electric motor includes a transformer BK, a base 3 for placing an electric motor 4, an arm 2 fitted onto the motor shaft 6, vertical supports 1 connected vertically to the left and right sides of the base, and either end of the arm can rest on the vertical support. The upper part of the arm has a slot, into which a key 8 is inserted, and the key can extend into a keyway 7 on the shaft. The output terminal of the motor winding is connected to the secondary winding of the transformer BK. An ammeter A is connected in series between the secondary winding of the transformer BK and the motor winding. The primary winding of the transformer is connected to the mains power, and a voltmeter V is connected to the secondary winding of the transformer. The secondary voltage of the transformer is about one-quarter of the mains voltage.
[0012] If the motor is single-phase, the transformer is also single-phase; if the motor is three-phase, the transformer is also three-phase. Figure 3 The motor in the transformer is three-phase, and the transformer is also three-phase. Its primary winding is connected to the mains power supply phases A, B, and C, and its secondary winding is connected to the motor phases a, b, and c. The primary voltage UBC is 380 volts, and the secondary voltage Ubc is 100 volts. The secondary voltage is about one-quarter of the primary voltage. This reduces stall torque, avoids unnecessary damage to the motor, and also reduces energy consumption.
[0013] The method of use is to place the motor on the base and fix it, put the arm body on the motor shaft, rotate the motor shaft so that the keyway on the shaft is aligned with the slot on the arm body, insert the key body into the slot and extend it into the keyway on the shaft, turn on the power, if the motor rotates in the forward direction, one end of the arm body contacts a vertical block, blocking the motor; if the motor rotates in the reverse direction, the other end of the arm body contacts another vertical block, blocking the motor; record the current (locked) indication of the ammeter, then turn off the power to the motor and remove the arm body.
[0014] By comparing the detected locked-rotor current with the benchmark locked-rotor current, the manufacturing quality of the motor can be determined, such as whether the number of turns in the stator winding is insufficient, whether the air gap of the motor is too large, whether the stator and rotor cores are aligned, and whether the conductor bars of the cast aluminum rotor have shrinkage cavities or slag inclusions.
[0015] When the boom is in a horizontal position, there is a gap between the boom and the vertical block. When the center height of the motor is negative (the center height is allowed to have a certain error), it can prevent both ends of the boom from contacting the vertical block at the same time (when both ends of the boom contact the vertical block at the same time, the contact between the motor and the base will be unstable). However, when the motor is powered on, the boom will rotate, and the boom will collide with the vertical block. To buffer the impact, a blind hole 11 is provided in the vertical block 1, and a spring 10 is placed in the blind hole, with the upper end of the spring protruding from the blind hole.
[0016] Because the key body has a certain width (to ensure that the key body has sufficient strength), and the length of the slot is greater than the width of the key body, the thickness of the arm body is correspondingly greater than the length of the slot. This makes the arm body heavy and difficult to fit with the shaft. To reduce the weight of the arm body, the thickness of the arm body is half the length of the slot. A sleeve 5 that mates with the shaft is welded on the arm body. The slot is set on the sleeve. To prevent misalignment between the spring and the arm body, a pad 9 is welded to the lower part of both ends of the arm body. The pad can cover the blind hole 11.
Claims
1. A stall test device for an electric motor, characterized in that, It includes a transformer, a base (3) for placing the motor (4), an arm (2) fitted on the motor shaft (6), vertical supports (1) connected vertically on the left and right sides of the base, the arm is located above the vertical supports, and either end of the arm can be placed on the vertical supports. The upper part of the arm is provided with a slot, and a key (8) is inserted into the slot. The key can extend into the keyway (7) on the shaft. The output terminal of the motor winding is connected to the secondary of the transformer. An ammeter is connected in series between the secondary of the transformer and the output terminal of the motor winding. The primary of the transformer is connected to the mains power. The secondary voltage of the transformer is about one-quarter of the mains voltage.
2. The stall test device for an electric motor according to claim 1, characterized in that, A blind hole (11) is provided in the vertical pier (1), and a spring (10) is placed in the blind hole, with the upper end of the spring protruding from the blind hole.
3. The stall test device for an electric motor according to claim 2, characterized in that, The thickness of the arm body (2) is half the length of the slot. A sleeve (5) that mates with the rotating shaft is welded onto the arm body. The slot is set on the sleeve.
4. The stall test apparatus for an electric motor according to claim 3, characterized in that, A pad (9) is welded to the lower part of both ends of the arm body, and the pad can cover the blind hole (11).