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What is wrong with my solid state relay? (super-smart ATOT electrical people needed)

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From the FAQ section of the datasheet for the SSR relay:

Q : I have an SSR driving a load. The load turns on
okay, but never seems to turn off, unless I remove
power from the relay entirely. What might be happening?

A: This is normally a problem when using an SSR with a hig himpedance
load, such as a neon lamp or a small solenoid.
Loads like these often have relatively large initial currents, but
relatively small “hold in” currents. The result is that the off-state
leakage current through the relay (see previous section) is
insufficient to cause the load to turn on to start with, but
sufficient to keep it on, once started. The solution is to place a
power resistor, sized for 8–10 times the rated maximum
leakage current for the SSR in parallel with the load. Make sure
that this resistor has a high enough power rating for the
application. For example, for a 5 mA leakage current at 120
VAC, a resistor drawing 50 mA would be desirable. Using
Ohm’s Law, the resistor value becomes 2,400 ohms. This
resistor will dissipate 6 watts, so a 7.5 or 10-watt size power
resistor should be used.
 
As many have said, your test load is not what the device was designed for. But part of the explanation is in the device spec sheet, under "Off-State leakage (mA) Maximum: 7 mA". So, once the load circuit has a current initiated through it from a 3VDC supply switched on by the unit's Triac, and then you try to switch it off, the Triac still allows a leakage current up to 7 mA to flow through the test load. Is than enough to keep your LED indicator lit? Note also that the "Maximum Output Voltage Drop" is 1.6 V (typical for a solid state junction), so the 3VDC supply is well more than that, and your test load has about 1.5 VDC applied. That's often enough to light a LED, as long as the current available is sufficient.
 
stinkynathan said:
What's the application? Brewing, sous vide, or smoking?

<- Built a 240v HERMS brewing system last winter. 🙂
Click to expand...

Making hamburgers 😛

project2.jpg
 
It's ok, I'm an engineer.


Sounds like your shit's busted, man. That sucks.


$200 consulting fee, please.




As others have said, it uses a triac for controlling the output. A triac can only turn off when the voltage across it drops below a certain threshold, fairly close to 0V. 120VAC wall power crosses 0V 120x per second. So you can turn the triac on at any time, but you can only make it stop conducting current when it has no voltage on it.

A MOSFET is used to control DC.


More later...lunch is over now.
 
Last edited:
those little foreman grills were cool, my roommate had one that i used.

http://en.wikipedia.org/wiki/George_Foreman_Grill

The worldwide popularity of the George Foreman grill has resulted in sales of over 100 million units since it was first launched, a feat that was achieved in a little over 15 years. Although Foreman has never confirmed exactly how much he has earned from the endorsement, what is known is that Salton Inc paid him $137 million in 1999 in order to buy out the right to use his name. Previous to that he was being paid about 40&#37; of the profits on each grill sold (earning him $4.5 million a month in payouts at its peak) so it is estimated he has made a total of over $200 million from the endorsement, a sum that is substantially more than he earned as a boxer.
Click to expand...

holy shit
 
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