I'm working on a power interrupt test using RM1D500D10. The goal is to create a short power interruption with a control signal. However, when testing without a load, I'm encountering an issue where the voltage doesn't drop to 0V

I specifically chose this part because it doesn't have any internal capacitors at the output. The load itself does have some capacitors to prevent power interruption. Therefore, ideally, I don't want to connect the load until I confirm that the power interrupt test circuit is working as intended.

Any suggestions on how to address this voltage drop issue would be greatly appreciated. Thanks in advance for your help!

Below are 2 captures from the Datasheet



Control Signals:

• Pin#3: 15VDC, with an interrupt of 40ms
• Pin#4: GND

Output Signals:

• Pint#1: 270VDC
• Pin#2: No load, tied directly to CH4 - Differential Probe of Oscilloscope for testing.

 

Quite an interesting question here. I have not used an SSR on DC that I can recall. So the very first question is what are the ratings for the SSR being tested? Then, what is the test current? AND, how fast is the control voltage removal? The bad news is that very little in the electrical world is "Instant", while many things are "quite rapid."
And now that I see "No Load" as a condition, it becomes clear that it is not a valid test. With no current flowing there is not very much reason for the voltage to drop. It could be that the capacitance in the scope connections is quite enough to keep the voltage from dropping farther.
So as a first attempt to have a real world test, put on a load of 270K ohms , and measure the fall with that one milliamp current flowing.
Also, look at your circuit for the internal elements of the SSR. The trigger circuit will draw more than zero current and produce a bit of leakage that will keep the voltage at the output from dropping to zero.

 

That looks normal, without a load you are usually not going to see a low drop.
Can you not simulate a load if you do not want to use it on the final device, as already suggested??

 

That SSR have a small leakage feedthrough (0.1mA, below), so you see a voltage from that when measured with a high impedance oscilloscope input.
Add a 100kΩ, 1W load to the output and then measure.
With that load, the output should drop to no more than 10V.

 

Ahh, it does make sense now. I need the minimum load to bring it down to 0V.

 

Keep in mind that the voltage drop Vd, across an open SSR=I x internal resistance. And if I=0 the voltage drop is also close to 0.