torque switch?

[puckman31]

I am looking for a device i can use on my gear motor i can use to shut down the motor when it is working at a higher or more powerful rate. A shear pin is not working at this time, any ideas?

 

[dpc]

Current sensing relay?

David Castor

http://www.cvoes.com

 

[jraef]

A current sensing relay is the first line of electrical product to consider. A step up in in accuracy and repeatability would be a Shaft Power Monitor Relay or kW Relay. The difference is that a current sensing relay acts only on current, which may change with voltage fluctuations and therefore be inaccurate. A Shaft Power Monitor looks at what is called "Active Power" which is based on Power factor readings, and a kW Relay measures voltage, current and PF to determine true shaft power (kW). Both methods end up with better accuracy / repeatability.


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[electricpete]

power meter might get fooled under locked rotor conditions, right?

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[electricpete]

Never mind... I guess depends on the situation... could certainly be backed up by an overcurrent relay. Or else rely on detecting locked rotor before you get there.

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[waross]

Is your motor 1/50 HP or 50 HP? An easy solution for a 1/50 HP motor may not be applicable to a 50 HP motor and vice versa. What percent of full load on the motor do you want to limit at?
Is this a chain or belt drive or a C face mount?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[puckman31]

It is a 5 hp and I want the lower amp end of the motor that is chain drive . Thanks to everyone for their help.

 

[waross]

Use a spring loaded "dancer" or tightening sprocket on the drive side of the chain. Use a limit switch to detect excess displacement of the dancer. You may have to install a similar sprocket with a lighter spring on the other side of the chain.
Another option is to install a pivot on the motor mount with a limit switch that will operate when the motor starts to "climb the chain".

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Compositepro]

I've seen motors mounted on hinged plates with adjustable spring and micro-switch. Crude but very effective. For greatest sensitivity you want the chain tension and motor weight force vectors to pass through the hinge pivot point so they have no effect on the spring setting.