Problem with the electrical cabinet!!! No power supply, but there is a signal!
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A couple of days ago, it was time to turn on the power for the pump in my installation. My mentor supplied power to it, and the signal light was green, so I thought there was power available; yet when the motor was started, it didn’t rotate. However, the signal light turned red! At that point, my mentor checked and found that there was indeed power at the output terminal of the electrical cabinet; yet the motor still wouldn’t rotate. Later, my mentor said, “Oh! I understand now!” but by then I had already left work. I don’t know what the cause could be. Please, someone knowledgeable can explain what’s going on!!! Thank you!!!
Check the circuit. According to what you said, the red light came on after startup, and there is no power at the output terminal. Did you not check whether there is power on the motor? Check it; the problem will be identified soon
You didn’t specify what initiated it; if it was started directly, then simply check the circuit once to identify the problem. If it is variable frequency or some other starting method, then the starting settings and circuits need to be checked.
Check whether there is electricity at the lower end of the AC contactor; if so, check the motor terminals!
Examine one by one, from the power supply inlet section to those attached at the ends
The output terminal of the electrical cabinet is powered! That’s strange; it’s better to go to the motor side and check there as well to see if there’s power. The problem is likely to be with the motor or the cables
OP, does your electrical cabinet have phase sequence protection? If it is checked, an incorrect phase sequence can also cause failure to start.
By saying that there is voltage at the output terminal, do you mean that the voltmeter shows voltage on the cable at the motor cable outlet cabinet? If that’s the case, it’s a problem with the motor. In your case, it is very likely that the drawer is in the test position rather than the working position; as a result, there is no electricity at the cable terminals
I don’t know whether your cabinet type is GCK, GGD, or something else; I’m also not aware of whether the low-voltage cabinets operate with red lights or green lights. In the case of low-voltage systems, many manufacturers use different approaches, unlike in high-voltage systems where red lights are used as a standard. If the voltage is low and the machine is in stop mode, yet there is electricity at the cable terminal, first check whether the motor is started by an inverter; if it is started via an inverter, this could be the cause. With inferior-quality inverters, red light will appear on the test pen when detecting induced electricity in stop mode ； Second, if a voltage is detected at the cable connector using a digital multimeter, it may be due to a stray alternating electromagnetic field caused by stray currents.