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Discussion Starter · #1 ·
I recently purchased a second hand reversing contactor. Although it doesn't look like it has ever been installed.

But when I have tried to trip either contactor I don't hear anything (no click).

I have done more research but I can't see anything that would make it more complicated than just applying 12v. I started by trying to trigger it through some 12v relays but when that failed I started to just manually touch the 12v wires on the terminals.

If it were only a problem with one side I would call it bad luck. But what are the chances of both sides being dead? That makes me think there is possibly more to this.

Any ideas? Is there some safety feature that is tripping me up?
It is a ZJQ-672.

I'm not overly concerned if it is dead but I didn't want to give up on premiturely.
If it is dead I will just use multiple single contactors controlled by my arduino.
 

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It's possible those coils require higher voltage. For example a 48V forklift would use 48V coils and 12V is too low. Such equipments don't use 12V systems. You might try a quick touch with higher V.

major
 

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How much research did you really do?

The ZJQ contactor series is designed for use in DC circuits and provide switching functions for devices such as traction drives, pump motors and electric vehicle applications.

  • Rated Current - 300 Amps
  • Voltage Coil Options – 72V
  • Coil Power – 35-40W
  • Rated Voltage of Contact Circuit - 6 to 80 Volts DC
  • Dielectric Voltage Strength - 50Hz 1000V AC 1min
  • Current Volt Drop of Main Contact at 100A - Not above 80mV
  • Operating time, Contact Makes & Contact Brakes - >30ms
  • Mechanical Life - 100 thousand times
  • Electric Life - 20 thousand times
  • Weight 7.25 lbs



 

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If it is dead I will just use multiple single contactors controlled by my arduino.
1. A reversing contactor has two mechanical states, multiple relays need extra stuff for the same safety level, to prevent a dead short (i.e. the arduino has to sense the voltage on all of the contacts and ensure they open/close in the right sequence and aren't stuck).

2. Ever consider a contactor rewind? for 72v to 12v you would conceptually take the wire off, make 6 even strands out of it, put the wire back on in parallel. I don't know how well it comes apart.
 

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Discussion Starter · #6 ·
1. A reversing contactor has two mechanical states, multiple relays need extra stuff for the same safety level, to prevent a dead short (i.e. the arduino has to sense the voltage on all of the contacts and ensure they open/close in the right sequence and aren't stuck).

2. Ever consider a contactor rewind? for 72v to 12v you would conceptually take the wire off, make 6 even strands out of it, put the wire back on in parallel. I don't know how well it comes apart.
Not sure I am keen to rewind the contactors. I think I am more confident getting the arduino to do the protection.
 

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Discussion Starter · #8 ·

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Hi Galderdi
Post a picture of your reversing contactor
Mine uses coils that are exactly like the ones on the separate contactors - the key to the reversing contactor is just the frame that supports the contacts and springs

You may be able to just take it to bits and swap over coils from another contactor
 

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Discussion Starter · #10 ·
Here is a pic,

Yeah that's another great idea.

The great news is that I don't plan to install any of this until around December so I have pleanty of time to experiment.

My first attempt will be using a step up circuit. I have one on order. I'll let you know how it goes.

Before I even go that far I will apply 72V (6x 12v batteries) to it and see if it operates.
 

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