使用电机电路分析进行 WYE 启动 DELTA 运行电机测试

When the inertial load of the process flow is high, a six-lead motor is usually used because it can be connected in WYE configuration at startup to limit the current, and then automatically switched to DELTA configuration by the motor controller after a certain speed is reached.

Testing was performed on the motor junction box.

As with many motors, a simple way to test a six-lead motor is to go directly into the motor junction box. After confirming that all “locking”/”marking” requirements have been followed and checking for voltage on the motor leads, the junction box can be safely opened
. If the motor leads from the controller and the internal motor leads are labeled, note the connections. If they are not labeled, mark them with colored tape or other markings so they can be properly reconnected after testing. Disconnect the motor leads from the starter’s internal motor leads or from the terminals inside the box.

The wires or terminals inside the motor should be numbered from one to six. As a check, you should be able to test the electrical continuity between terminals/wires 1-4, 2-5, and 3-6. These are your phase wires (A, B, C, or 1, 2, 3).

When using the ATIV to test a motor, the instrument can be connected to terminals/wires 1-4 of phase 1, terminals/wires 2-5 of phase 2, and terminals/wires 3-6 of phase 3. All three windings should be tested individually using INS/grd.

To test the motor in a WYE configuration with an AT33IND or AT5
, you must short-circuit terminals 4, 5, and 6/wires. These wires can be secured together with bolts or using appropriately sized jumper wires.

The tester can then be connected to terminals/lines 1, 2, and 3. This configuration requires only one INS/grd test.

Testing on the motor controller

Depending on the cable size and control cabinet configuration, there are many different methods for testing a six-lead motor from the motor controller. In the cabinet shown below, the method used is…:

ATIV
is tested normally between points 1-4, 2-5, and 3-6 on the bottom of the RUN and DELTA contactors. Similarly, each winding should be tested separately for INS/grd.

Leads 4, 5, and 6 of the AT33IND and AT5
need to be shorted together. This can be done using the jumper at the bottom of the DELTA or WEY contactor, or by forcing the WEY contactor in some way. After shorting, connect the instrument to cables 1, 2, and 3 at the bottom of the RUN contactor.