Solid state relay, back feeding

Good Morning.

Hey the place hasn't changed a bit.

MCC Cans have two Nema 2 starters, 120 v coils, pick up current 1.91 (cold) holding current is .065

E-300's have (3) 3 amp (@120v) solid state relays, I have two E-300s in a dual motor MCC. Rewiring to create a double redundancy for overload and control.
Using the first unit, r-14 and r-24 to eneregize each of the starter contacts.
Using second unit to energize motor "A" or "B" in the event of a single motor failure.
This would create a 120 v @ .065 continuous back feed on either of the first units SSRs

Checked internet, checked Rockwells knowledge base and forum.

Best I have gotten is twice the current rating of the SSDs of the back feed (maybe) .

I do not see a leakage or doping issue, Can anyone clarify with first hand experience any short or long term problems created by this configuration

Your time and attention is appreciated. Thank you

Hey the place hasn't changed a bit.

MCC Cans have two Nema 2 starters, 120 v coils, pick up current 1.91 (cold) holding current is .065

E-300's have (3) 3 amp (@120v) solid state relays, I have two E-300s in a dual motor MCC.

Click to expand...

I think I follow so far.

Rewiring to create a double redundancy for overload and control.

Click to expand...

Hmm. Can you post a sketch of the proposed schematic?

3 outputs per E300, 2 E300's ... one overload for each of 2 motors? ..

Using the first unit, r-14 and r-24 to eneregize each of the starter contacts.
Using second unit to energize motor "A" or "B" in the event of a single motor failure.
This would create a 120 v @ .065 continuous back feed on either of the first units SSRs

Click to expand...

I've never used SSRs to switch coils at work. Just on hobbies, and I have not successfully protected the SSRs. They kept blowing up. From transients that I did not deal with, presumably

Checked internet, checked Rockwells knowledge base and forum.

Best I have gotten is twice the current rating of the SSDs of the back feed (maybe) .

I do not see a leakage or doping issue, Can anyone clarify with first hand experience any short or long term problems created by this configuration

Your time and attention is appreciated. Thank you

Click to expand...

A schematic would help ... and just to confirm, SSR is switching 24VDC?

It sounds like you are using the 193-EIO-43-120 control module.

As far as I know, those control modules have true relay contact outputs, not solid-state. Are your "SSRs" added by you for interposing functions, or are your motor starters solid-state ?

Is the 120V derived from a control transformer in the bucket ?

This is definitely going to require a schematic.

thingstodo said:

I've never used SSRs to switch coils at work. Just on hobbies,

Click to expand...

I was thinking of using 4 SSR's on my air conditioner compressor power control, but decided against it.

I am adding a SLC in my utility room to monitor the power from the main electric meter and the controlled meter for the compressor. The controlled meter power is much cheaper from the utility, but at the cost of they get to turn it off frequently when there is a high demand. Having a water heater controlled doesn't matter - not going to runout of hot water. But the compressor gets shut off a lot, and the furnace doesn't know so the blower is running & blowing hot air for a while.

The plan is that when the controlled power is shut off to switch over to the more expensive main power, then back when it comes back on.

The original idea was SSR's but then I started thinking, as this thread proves, that there might be some back current sending power between the meters, and if the controlled meter was off but sensed power there could be a problem. I bought a 2NO2NC contactor.

Thanks Ken, you are correct. The unit is a 193-EIO-43-120 control module Ser B

I couldn't find anything that corroborated my thought it was an SSR. The manual
https://literature.rockwellautomation.com/idc/groups/literature/documents/um/193-um015_-en-p.pdf for this unit calls it an output relay, which can be programmed to be a NO or a NC. (That's the part that thru me)

The motor starters are coil driven NEMA 2. It's a Rockwell MCC

The control power is distributed thru the MCC from a fused buss.

Thanks again Ken, and all who participated.