Help with SSR (solid state relay)

R

RancidWAnnaRIot

EspantaPajaros
Joined
Feb 19, 2004
Messages
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Hello,

i plan to use a SSR i have to drive a DC motor. i decided to test the the relay with a resistor, but connecting it as the load to the SSR, and then measuring the current flow to the resistor when i apply 3-32V to the control.

the thing is.. i never get a current reading.. also, it seems like the output terminals are shorted.. i apply 5V on one and i read alittle less than 5 on the other, even when my control is grounded.. i'm confused on how this things works


i thought i just ground the (-) terminal on the control (input), and then when i apply anything from 3 - 32V on the (+) terminal of the control (input) it shorts the two output terminals.. where i have 5V on the (-) terminal of the output, and connect the (+) output terminal to load..

isn't that how it should work?? yet.. the output terminals seem to always be shorted.. there is a slight.. extremly slight change when i apply a voltage to the positive contro linput.. but i don't know.. like i siad... i'm not measuing a current either during all of this..
 
A relay is basically a switch, so basically you have a bad relay, you should apply current and on one end not get any reading at all.

~Adam
 
CleanSlate said:
A relay is basically a switch, so basically you have a bad relay, you should apply current and on one end not get any reading at all.

~Adam
Click to expand...

what a load of crap.. you serious?.. damn it.. i thuoght it might be bad.. but this is the first time i work with a relay.. so i wasn't sure..
 
Here's a fool proof way to tell: open the relay so that it shouldn't be flowing current to both ends than hit both ends with current and see what happens.

~Adam
 
The answer may not be as simple as just a broken relay. SSR are not all created equal. Some require very specific voltages to turn on, if they are optically isolated for example.

What model of SSR are you trying to use?
 
Pull up a datasheet on the part, first off, and make sure you've got a unit that works for DC. A lot of SSR's are glorified thyristors, in which case they'll never turn off unless you're running AC.

Beyond that, an SSR isn't necessisarily identical to it's electromechanical cousins. The load control side may very well have a significant forward voltage drop, and/or significant leakage current... Make sure you've got the whole thing hooked up right, and test it with a load similar to that for which it was designed...

Good luck
 
The Brain said:
The answer may not be as simple as just a broken relay. SSR are not all created equal. Some require very specific voltages to turn on, if they are optically isolated for example.

What model of SSR are you trying to use?
Click to expand...

I have the data sheet. it's a Kyotto SSR model. KG1010D

it's a DC relay..

the input can range from 3-32V output max is 10A and 120V.

i'm 100% sure it's a DC relay..

here's a link to the data sheet


http://cn.100y.com.tw/pdf_file/KG1005,10,25,40,2010D.pdf
 
RancidWAnnaRIot said:
Hello,

i thought i just ground the (-) terminal on the control (input), and then when i apply anything from 3 - 32V on the (+) terminal of the control (input) it shorts the two output terminals.. where i have 5V on the (-) terminal of the output, and connect the (+) output terminal to load..
Click to expand...

Connect your 5V source to the the positive of the load. Connect the negative of the load to the positive of the SSR's output and the negative of the SSR's output to your 5V source ground.

(+5V)------------ (+) LOAD (-) -------- (+) SSR out (-) ------ (GND)

Also make sure your not exceeding the rated current of the SSR. Some of them list the rated current assuming a heatsink is attached.

P.S. The control current will be almost nothing.
 
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