I need advice. I have no experience at all with electronics.
I'm a machinist. I’m repairing a machine with a 1/2 hp electric motor. 110v.
I need to replace the diode that stops power from back feeding when a switch is applied.

it’s just a simple motor that runs a turn table in a jet wash cabinet.
the table comes on when the pump is turned on.
but I have a separate switch that just turns on the table as a jog function.
I need the power to not back feed to the pump when the pump is off and I need to turn the table to a specific position to unload whatever is being washed.
My original is literally destroyed and I can get no information from it.
I’m pretty sure it’s a simple diode rated to handle the load.
Unfortunately I have no understanding beyond that.
Could someone please direct me to the correct one?

 

At a guess, the half-horsepower motor runs the pump, and a different motor runs the turntable.
What sort of motor runs the turntable?

 

At a guess, the half-horsepower motor runs the pump, and a different motor runs the turntable.
What sort of motor runs the turntable?

Actually the pump is a separate 2hp motor.
The table is turned by the 1/2hp motor.

 

Actually the pump is a separate 2hp motor.
The table is turned by the 1/2hp motor.

Both the pump and table are turned on by a contactor
Since both motors are energized by the same contactor if I supply current to the one
I need a diode to prevent current running up the wire to the other.

 

Half a horsepower is 375W.
375W at 110V DC is 3.4A.
Allowing for efficiency and start-up inrush, you need about a 10A diode rated at 200V.
10A diodes tend to be pcb mounted, so I would suggest connecting a single diode from a bridge rectifier such as this one
https://uk.rs-online.com/web/p/bridge-rectifiers/8122240?gb=s
just for ease of mounting and connection.
Connect either of the AC terminals to the supply and the + terminal to the motor.

 

Half a horsepower is 375W.
375W at 110V DC is 3.4A.
Allowing for efficiency and start-up inrush, you need about a 10A diode rated at 200V.
10A diodes tend to be pcb mounted, so I would suggest connecting a single diode from a bridge rectifier such as this one
https://uk.rs-online.com/web/p/bridge-rectifiers/8122240?gb=s
just for ease of mounting and connection.
Connect either of the AC terminals to the supply and the + terminal to the motor.

 

Thank you very much.

 

Just to be sure.
This is a ac motor. The information online says that converts ac to dc.
If I only use one connection to and one connection from as you posted then I will still get ac to my motor right?

 

This is a ac motor.

In that case, it never had a diode in its supply.

 

Just to be sure.
This is a ac motor. The information online says that converts ac to dc.
If I only use one connection to and one connection from as you posted then I will still get ac to my motor right?

I doubt that the online information is complete. AND, certainly we need more information to provide useful advice. Otherwise there are only guesses.
I suggest that the TS read the label on the turntable 1/2 HP motor, and let us know what it actually is.
Now for a question: What controls does the machine have??
Is it a start-stop-Jog set of push buttons? or a single knob switch? OR is there an on/off switch with a separate jog switch??
How was the "jog" function controlled??
What was the burned-up diode connected to??? Can the TS tell us what it was connected to??

 

I’m pretty sure it’s a simple diode rated to handle the load.

You are pretty sure it is a diode... The diode you want, has any numbering stamped ? Can you attach a photo ?

 

There are people around here who know a whole lot more than me about industrial controls, but . . .

Based on your descriptions, a simple diode will not do what you want. Both motors require AC to operate, and one or more diodes cannot get you the isolation you want while delivering AC to the motor (s). A TRIAC is a single electronic component that can block AC, but not without a control circuit. This is what is in a solid-state relay (SSR). Another option is a conventional, electro-mechanical relay.

If you replace the contactor with two separate relays, you can power the motors in any combination - pump only, turntable only, both. The same thing can be done by leaving the contactor in place as a master on/off, and placing the two relays after the contactor, one for each motor.

ak

 

What we have no clues about is the 2 HP motor and what kind of motor the turntable motor actually is. And the item that burned up so completely might even have been a snubber, not a diode. We do not even know if the arrangement with a diode ever actually worked as intended, or if it is an additional control to be added and the first effort failed.
In addition, we do not know if the contactor was switching one, two, or three circuits.