Unknown Piece of Electrical Equipment (pics) Identify

In summary, the conversation is about identifying a piece of electrical equipment that the original poster has never seen before. The equipment seems to be a custom cabinet with six contactors, possibly used for dynamic retarding of traction motors on mobile mining equipment. The equipment also includes rectifiers and DC output contactors, possibly for a large battery charger. The conversation ends with the original poster asking for more closeup pictures and clarification on the purpose and location of the equipment.
  • #1
Greetings all,

I need some help identifying a piece of electrical equipment for work.. I myself am a mechanical engineer and have never seen something like this. I have attached pictures below.


My initial thoughts was that it was some kind of loadbank or transformer. ANY help would be greatly appreciated. Thanks

Engineering news on Phys.org
  • #2
They are six contactors. The black housing is an arc chute. It contains the arc when the tips of the contact are broken. A low voltage power a coil which creates a magnetic field to close a circuit with a larger voltage. The larger coil behind the arc chute is a blowout coil

As for what they are feeding, it could be anything. Likely, motors

I do maintenance on contactors of this type at my work daily,

Adjusting coil voltage for closing, drop-out voltages, changing pitted contacts tips, pitted arc chutes, etc...

The smaller wires coming from the contact are for numerous things. It needs to power the coil, it needs a supressor across the coil when the circuit is broken (resistor and cap) it needs also feedback so the controller knows that the tips are closed when the command to close is given. It also needs to know if a contact closes without a signal applied to the coil, which would be bad.

In my work these contactors are used on komatsu haul trucks for dynamic retarding of traction motors. When you want to brake an electric motor, you can release it from its supply voltage and its inertia ensures it is generating. An electrical load attached to the motor (through contactors) ensures the motor can be controlled to brake.

Honestly, if I had to guess, I would say this is from some piece of mobile mining equipment. Such as a B&E or P&H mining shovel or blasting drill... attached is a pic I took of a contact cabinet from a P&H drill (note the contactors)

I'm know what u have is a contactor cabinet - I don't know for what exactly..


  • IMGP0192.jpg
    40.1 KB · Views: 408
Last edited:
  • #3
What are the six vertical structures that are red with white dots? Can you provide a closeup of these?

And closeups of the other equipment in the cabinet - need individual closeup images!

But at a guess this is a custom electrical cabinet for some piece of machinery; I used to work for an electrical controls company and everything that goes into a plant had to be enclosed in a cabinet like this (painted to match their particular code).
  • #4
Guys, I really appreciate the help. Foiwater, great response. Ill do some research on what you suggested.

These are the only other close up pictures I have. I would have more pictures but I am not at this particular job site.

They are of the two components in the upper left hand corner and a semi-closeup of the six contactors in a different unit.

Thank you.


  • Unit 1 Int Comp AB Info.jpeg
    Unit 1 Int Comp AB Info.jpeg
    32.7 KB · Views: 529
  • Unit 1 Int Comp ACME Info.jpeg
    Unit 1 Int Comp ACME Info.jpeg
    29.5 KB · Views: 481
  • Unit 2 Inside.jpeg
    Unit 2 Inside.jpeg
    35.1 KB · Views: 450
Last edited:
  • #5
I am thinking the whole thing is a rectifier and DC output contactors, load break, some are paralleled. Is this sitting in somewhere mothballed?

Why do you need it identified? Where are you located?
  • #6
If rectifiers are involved, possibly a very large battery charger?

Suggested for: Unknown Piece of Electrical Equipment (pics) Identify