Motor backspin detector 1

[LionelHutz]

Hello;

Can you give me some leads for a device to connect to the leads of a 4.16kV motor which would tell me if it is rotating?

 

[roydm]

If it's backspin prevention you are after there are devices to attach to the motor that will prevent that, some sort of ratchet device that flings the pawls out once the motor is running. I have seen them on vertical pumps.
It's common in mining also for uphill conveyors but there they use something on the gearbox.

 

[LionelHutz]

burnt2x

We've already suggested a flow sensor as a possible solution. The motor isn't accessible so they won't be installing a proximity sensor.

 

[burnt2x]

A very tough problem I guess!
We do have another unit employing DC braking system, but we used feedback from a tacho-gen mounted on the shaft of the motor to prevent starting of motor when backspinning. The gadget kicks-on when the motor is backspinning, bring the rotor to a stop before the softstarter engages to speed-up the motor.
But, as you said, they won't be installing a sensor due inaccessability!
If your pump is a vertical well pump, roydm's suggestion could be a solution. The equipment is just attached to the non-driving end of the shaft; uses steel balls that locks-in on backspin, but stays out on the correct rotation!