checking a solid state relay (SSR)

I have a machine that has a DC motor.
It has a brake using a SSR.
I bought this machine new 15 years ago and have used it every day since.:grin:
now when I try to run the machine, it throws the AC 8 amp breaker. It pulls up to 20 amp before throwing the AC breaker.:-(
If I unhook the SSR, the machine runs fine except when it shut off it keeps spinning, no brake.
I am trying to check the SSR.
if I hook up #3 and #4 and turn on the machine I have 110V at #3.
It looks to me like #1 and #2 should be open at some point. what opens and shuts #1 and 2?
When I push the start button, the DC motor spins and then when the timer shuts off the motor I would assume this would close #1 and #2 to short out the DC motor to work as a brake, but that is what has quit.
I bought a new relay and it didn't help. I think the SSR is good but don't know what should happen. when I turn the power off on the relay nothing changes at #1 and #2.
what am I doing wrong when checking the SSR?

Hi,

safety first: be careful. you are working on dangerous mains voltage!

Disconnect the whole machine from mains before you touch, connect or disconnect a wire.

*****

what am I doing wrong when checking the SSR?

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I assume the brake needs power to release the spindle and it may turn. If the power to the brake is disconnected then it brakes and the spindle stops running.
Therefore you need to connect the wires at #1 and #2 to release the brake. Can you confirm this?

There may be many informations around with a description how a SSR works. Read them carefully.

* #3 and #4 are the connections to an LED (inside the SSR, you can´t see it). An LED needs current, DC current .. and the voltage is of minor interest. Therefore to simply test the voltage is about meaningless.
(In detail it depends on the internal circuit of the SSR)
* you could connect a current meter is series with the line on #3 (or #4), select DC current. and tell us the measured values.

if I hook up #3 and #4 and turn on the machine I have 110V at #3.

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This tells me you measure the (AC?) voltage against earth ground or something else.
If you want to measure the voltage then connect one wire of the meter to #3 the other wire to #4 and select "DC voltage". You could tell us the result of the measurement.

***
Connections to the brake:
When the LED is ON, then typically the relay connects the terminals #1 with #2. This switch is controlled by the light of the LED.

Klaus

Connections to the brake:
When the LED is ON, then typically the relay connects the terminals #1 with #2. This switch is controlled by the light of the LED.

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I have #3 and #4 hooked to the machine.
Can I use an ohm meter to tell if #1 and #2 open and close based on whether #3 has power or not?
#1 goes to one side (wire) of the DC motor and #2 goes to the other side of the motor. I'm assuming that when 1 and 2 are connected that is what stops the motor by shorting out the 2 wires
when I use an ohm meter to test between #1 and #2 it shows closed regardless if #3 has power or not.
I bought a new SSR and I get the same reading.
either both are bad or I am doing something wrong.
You statement above I agree and understand that I think, that is why I am confused on my results of my test.

when I use an ohm meter to test between #1 and #2 it shows closed regardless if #3 has power or not.
I bought a new SSR and I get the same reading.

Click to expand...

Need to disconnect the motor wires before measuring resistance, at least from one of the terminals. Did you?

According to your previous report, the problem is false open (never breaking) not false close (always breaking, respectively shorting the motor supply). So we would expect that the SSR never closes, because it's defective or the #3/#4 input signal is never applied.

As KlausST explained, you need to measure the voltage between terminals #3 and #4 to determine if the control voltage is present. There must be a voltage according to the SSR type plate, e.g. 3 - 24 VDC.

Yes, motor is unhooked, the only thing connected at 1 & 2 is the ohm meter.
3 & 4 are hooked to the machine like normal. I have 115v currnet at the SSR on #3. the #4 appears to be the common
My reading on the ohm meter is closed regardless if there is power or not at 3.

I took a closer look at the SSR type plate and noticed that it's an AC (triac or scr) solid state relays. I wonder how it's working for a a brake, it can only work as a kind of emergency stop which can't be released before the motor comes to standstill after being activated.

And yes it has 90 - 280 VAC control input. If you see the SSR closed (0 ohms) with no control input, it has been destroyed by massive overcurrent. But the finding seems to contradict your previous report about no brake effect.