# Hidrostal pump wiring issue



## JRaef (Mar 23, 2009)

If memory serves me correctly, those are what they refer to a "backup thermal sensors" that are embedded in the windings of the motor. The moisture / thermal sensor that you have is looking at the oil in the housing. These other sensors are in the windings themselves. In Explosion Proof applications, these are required in some jurisdictions even though you have a motor overload relay in the starter. Mosr people in the US don't use them unless they are running the pumps on a VFD.

If you want to use them, you need what is called a "Thermistor Tripping Relay". You wire those sensor circuits in series with each other and the Thermistor Relay measures the resistance of the entire circuit. As the winding temperature increases, the resistance changes suddenly at a particular threshold, the relay picks that up and changes state to drop out the starter circuit.


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## John Valdes (May 17, 2007)

Or they could just be temperature sensor leads that can be connected to a temperature controller.
They could be located in the windings and on each bearing housing.

The distributor should be able to explain what these leads are for. Go to the manufacturer if the distributor cannot help you.


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## Zenerohmma (Oct 24, 2008)

John Valdes said:


> Or they could just be temperature sensor leads that can be connected to a temperature controller.
> They could be located in the windings and on each bearing housing.
> 
> The distributor should be able to explain what these leads are for. Go to the manufacturer if the distributor cannot help you.




I'm going to guess they are for low voltage instrumentation devices that could be added on?

I have never directly worked on this type of a system but I'm going to make an educated guess and think the low voltage wires could be used for devices that measure flow, pressure, level, process monitoring devices.

Not sure but I would definitely contact the manufacturer a request a full wiring diagram for the pump.


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## John Valdes (May 17, 2007)

Zenerohmma said:


> I'm going to guess they are for low voltage instrumentation devices that could be added on?
> 
> I have never directly worked on this type of a system but I'm going to make an educated guess and think the low voltage wires could be used for devices that measure flow, pressure, level, process monitoring devices.
> 
> Not sure but I would definitely contact the manufacturer a request a full wiring diagram for the pump.


Knowing the motor industry fairly well I can say with confidence the leads are connected to temperature sensing probes such as thermistors or temp switches like "Klixons".
The sensors could be anything from a thermocouple to a switch.
There is no possibility these leads can do the things you mention as they are located in the motor itself.
I do agree the distributor and finally the manufacturer be consulted as to the leads in question. But only to verify what type of temp sensor is present.


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## Fixastang (Sep 4, 2012)

Thanks for the suggestions. We are still waiting to here from the vendor. I'll keep everyone posted when we hear from them.


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