High amperage pressure switch

[BWSwede]

I am working on another way to skin the cat. This one involves an electric motor/reservoir to run two very small hydraulic cylinders.

I need to be able to cut power to the motor when the system pressure reaches 1500 psi or so. The motor up in that pressure range could be as high as 180 amps at 12 volts.

I have been looking for a pressure switch that can handle that amperage but I have been unable to find one. Am I missing something?


TIA,
BWSwede

 

[Industrial Toys]

Why not just get a contactor? Or starter solenoid?

Not a hydraulic guy, but don't you need an accumulator if you are going to use a pressure switch that way? Otherwise the switch will just cycle rapidly. Normally the pump stays on and goes into relief at some preset pressure. Like I said, I am not a hydraulic guy.

 

[dickfoster]

Why not just get a contactor? Or starter solenoid?

Not a hydraulic guy, but don't you need an accumulator if you are going to use a pressure switch that way? Otherwise the switch will just cycle rapidly. Normally the pump stays on and goes into relief at some preset pressure. Like I said, I am not a hydraulic guy.

^What he said^
Or maybe go to some kinda super duper FET based solid state affair that will handle that kind of current so you don't have burned out contacts to deal with.

 

[Industrial Toys]

FETs just like to go snap, crackle and pop, like in inverters. Generic Solenoids are dirt cheap and best of all, simple.

 

[BWSwede]

Great idea with the starter solenoid! That is what I'll do.

Thanks,
BWSwede

 

[BukitCase]

One word of caution on using a solenoid - I got curious because I'd never had occasion to check it, so I hooked up a DC clamp-on ammeter around the solenoid wire on my case backhoe - with just the solenoid engaged, it pulled over 40 amps

Dunno if car types do that also, but you may wanna check on this before getting too far along - might need to run the solenoid with a BIG relay, I've not seen a lot of pressure switches that can handle that kind of current...

Also, most pressure switches (even hydraulic ones) normally have a "deadband" adjustment - also known as differential pressure. Widen that adjustment a bit and chatter shouldn't be a problem... Steve

 

[joefromga]

This one will handle 80 amps and requires very little current at 12v DC. It's just a giant relay. They also sell a 200a version.

You could also use an hvac contactor but that would need 24v ac to activate it.

 

[LD1]

SO what is it you are working on?

I dont Whats the benefit to stopping the motor once 1500psi is reached? Without an accumulator setup, the very moment you want to do anything with the hydraulics, you will have pressure drop and the motor will have to come back on? So the idea of building up 1500psi then stopping......what does that gain you?