Motor Starting SSR Question - Page 1
Forum section: electronics / beginners

author: RyanG
author_rank: Regular Contributor
timestamp: September 07, 2017, 06:07:18 am
content: So, I made an adjustable time SSR. It can turn on for anywhere between 250ms and 750ms using a pot. I am using it to connect/disconnect the start windings in the motors we use where I work. They work fine on all the motors except on the one motor that has a reverse function. That motor and its wiring is in the schematic that I attached. I pull 110v from SMP-CT and SMP-NIL to power the board. The connection that I am making or breaking with the SSR is between SMP-Z and TSA-2. The motor will run fine in forward, but not in reverse. The SWSR is the switch that reverses the motor. I am confused as to why my relay will not work when that switch is engaged. I have tested my relay on multiple motors. All of them run forward with no problem. Any help would be appreciated. Thanks in advance. The second attached schematic is the SSR.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: September 07, 2017, 08:08:16 am
content: Does the motor make a noise and try to turn, but with no power when reverse switch is thrown? If so, then the start winding is disengaged when you flip the reverse switch.As to why the SSR doesn't work the other way around, I am not sure, but you could test this by simply moving the leads from one side of the SSR to the other. If it reverse starts but doesn't forward start, then you know it is the SSR causing the problem (which it appears to be true, from the information that you gave).If it is the SSR, there is a solution to this, which is fairly simple. You can PM me if you find the above to be true and want to know the simple solution.

author: RyanG
author_rank: Regular Contributor
timestamp: September 07, 2017, 01:08:07 pm
content: I tried swapping the start winding side wires but not the 110 side wires and it did not work. The only idea that I had was how the capacitors are wired in the circuit. And, the motor hums like the start winding isn't connected but the run winding is. I was thinking about holding a led in parallel with the one in the opto triac to make sure the ssr is working.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: September 08, 2017, 12:42:38 am
content: Quote from: RyanG on September 07, 2017, 01:08:07 pmYes, at least you will get a light if the SSR is getting a signal, however, you could just put a meter on it. I don't know what SSR you are using, but assume the trigger side is DC<15mA fire. As far as the start circuit, yes I was thinking that the SSR may not like the caps on one side.EDIT: To see the LED or the meter in less than .75 seconds might be problematic, but could be feasible.

author: RyanG
author_rank: Regular Contributor
timestamp: September 08, 2017, 03:26:56 am
content: I built the SSR myself (the schematic is on the first post). I have tested it on multiple motors and it works fine, but I just can't get it to run this motor in reverse. I'm almost positive it has to do with the capacitors or maybe something to do with the relay being before the winding when the motor is run in reverse.

author: RyanG
author_rank: Regular Contributor
timestamp: September 08, 2017, 10:54:45 pm
content: I was looking around in the machines at work and I found that one of the after market modifications for the potential relays we currently use requires some rewiring of the motors internally, which might be the reason my board doesn't work. The modification moves the SMP-Z wire inside of the motor to a different position.

author: RyanG
author_rank: Regular Contributor
timestamp: September 10, 2017, 05:11:45 pm
content: Looking back over the machines here and the entire schematic for them I found that the wire I am moving to power my board is not hooked up to SMP-CT. It is hooked up to SMP-Y. Would that cause problems because of its location in the circuit when the reverse switch is engaged?

author: tpowell1830
author_rank: Frequent Contributor
timestamp: September 10, 2017, 11:34:49 pm
content: Quote from: RyanG on September 10, 2017, 05:11:45 pmHmm, yes I think it would be a problem because when the reverse switch is actuated, SMP-Y is neutral and you would not have power to fire the 555. Did you put an LED or meter across your control terminals of the SSR to check for pulse when the reverse switch is actuated?Edit: It would help to see the modified drawing of the circuit, as you explained.

author: RyanG
author_rank: Regular Contributor
timestamp: September 11, 2017, 12:46:45 am
content: I'm fairly sure that what I said is the problem, but I drew up the 2 circuits anyways for others to look at. I have the before and after. The red lines are the 110v connections and the blue are the ones that are being connected/disconnected by the SSR. The SMP-Z connector is also connected right to the end of the start winding rather than through the CS switch, which is the old centrifugal switch that has been disconnected. Apparently, hooking up a potential relay with the SMP-Y works fine though because that is how it works now.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: September 11, 2017, 03:21:57 am
content: Quote from: RyanG on September 11, 2017, 12:46:45 amYes, as I said before, when the reverse switch is actuated, SMP-Y is at the same potential as SMP-NIL, therefore 110VAC is not present on the 555 circuit, which means there is no pulse turning on the SSR. If you moved the wire for your 555 power from SMP-Y to SMP-CT, it should work.

author: RyanG
author_rank: Regular Contributor
timestamp: September 11, 2017, 08:55:05 am
content: Alright thanks. Once I actually pulled a machine apart and found that it was wired that way I figured that's what it was. I thought it was wired from CT the whole time.

author: RyanG
author_rank: Regular Contributor
timestamp: September 12, 2017, 08:35:27 pm
content: It works. Thanks for the help