Motor "Ground Check" lead

[augie47]

On a submersible pump installation, the motor has a wire labeled "ground check". The schematic does not address this lead.
I am awaiting an answer from the mfg, but, in the meantime, has anyone encountered a "ground check" motor lead ?

 

[iwire]

Nope ......... but it sounds cool.

 

[hurk27]

If I remember right it is a lead to test whether or not the windings have went to ground and or to use when meggering double insulated pump motors that would other wise not have this ability, as far as I know it just gets capped off.

 

[charlie k.]

Is this motor connected with a plug? Does it have a panel that controls it?
If so the ground check monitors the ground and removes power to the motor if the cable is disconnected or cut. It will also have a ground check relay at the controler. This relay usually needs to be calibrated to the cable length.
This type of setup is common in mining and tunneling equipment operating at higher voltages.

Charlie

 

[dbuckley]

Just confirming; there is a ground wire to the pump, as well as a ground check wire, yes?

When you have these setups, the ground check wire is connected to the motor frame somewhere other than the ground wire. Using a low voltage montoring circuit, you can check the integrity of the ground connection. Essentially, theres a power supply and a relay, and the power supply goes to the relay, then to the ground check wire. The other side of the power supply goes to the gound wire.

If the ground monitoring fails, then the relay opens, removing power to the device.

I know you guys dont use these connectors much, but the CEE17 series of industrial connectors are available with one or two extra pins ("pilot pins"), and this is often used for that type of connection. The ground pin contacts first, then the power pins, and then the pilot pins. Pull the plug and the pilot is first to break contact.

 

[voltage25]

Ground Check

Ground Check

The ground check wire is used with Ground Check monitoring equipment (example Startco SE-105). It has a zener diode connected between the frame (ground) and the Ground check lead (opposed to the ground wire which connects solidly to ground). The monitoring equipment will use this ground check wire to determine if you lose your true ground connection. Hence ground check.

Usually used in conjunction with Ground Fault devices. Typical on mining submersible pump applications over 300V in Canada