OK. I remember reading on CC a while ago about Joe K wanting to use an SSR to drive a small motor. It said that ssrs most of the time can't handle an inductive load and that you would need a different style ssr to run an inductive load. Does anyone have some ssr designs that will run an inductive load? i looked at the files that were attached but i don't think that i quite understand them. i made one of the designes that i saw and think that it might work. Could someone check to see if i did it right and if it would work? thanks.
different style ssr
- Thread starter Zane
- Start date
ErnieHorning
Supporting Member
This is the concept. All that this is trying to do is counteract the inductance with capacitance. The resistor limits the current through the capacitor.
You probably won’t burn anything up. It’s just that an inductor shifts the phase of the current with respect to voltage. The TRAIC is turned on at the zero voltage point and the current drops to zero at some point after. When the current comes back up, the gate sees the present voltage as a turn on value. The result is that the TRIAC appears to just stay on and never turn off. The snubber attempts to put the voltage back in phase with the current.
You show the capacitor as an electrolytic, which has polarity. This has to be a non polarized part, since we’re using AC. I’m showing you another layout, which is more compact, as only another way since I tend to make boards on the small side.
BTW, you can skip the snubber circuit by just using snubberless TRIAC’s. You only need to do this for channels that control an inductor.
You probably won’t burn anything up. It’s just that an inductor shifts the phase of the current with respect to voltage. The TRAIC is turned on at the zero voltage point and the current drops to zero at some point after. When the current comes back up, the gate sees the present voltage as a turn on value. The result is that the TRIAC appears to just stay on and never turn off. The snubber attempts to put the voltage back in phase with the current.
You show the capacitor as an electrolytic, which has polarity. This has to be a non polarized part, since we’re using AC. I’m showing you another layout, which is more compact, as only another way since I tend to make boards on the small side.
BTW, you can skip the snubber circuit by just using snubberless TRIAC’s. You only need to do this for channels that control an inductor.
ErnieHorning
Supporting Member
The best would be to fallow the layout described in the SSR How-To by Sean Bolf at http://computerchristmas.com/?link=how_to&HowToId=68, in particular the connector used for the input. Most of the current and future controller designs will be compatible with this SSR.
Check the Coop forum to see if there is a Co-Op going, to by these boards already made. This will be the cheapest and most reliable method of getting these boards. You still need to purchase the parts, which may also have a Co-Op, and solder the parts on.
I believe the recommend TRIAC is a snubberless one, so it should already accept a small motor. The TRAIC’s without a heatsink can handle up to 1 amp. Any more than that will depend on the heatsink used and the case that the SSR is mounted in.
I ran an animated deer on one channel last year without a problem. Realize that it was a small motor in parallel will lights, so your mileage may vary.
Check the Coop forum to see if there is a Co-Op going, to by these boards already made. This will be the cheapest and most reliable method of getting these boards. You still need to purchase the parts, which may also have a Co-Op, and solder the parts on.
I believe the recommend TRIAC is a snubberless one, so it should already accept a small motor. The TRAIC’s without a heatsink can handle up to 1 amp. Any more than that will depend on the heatsink used and the case that the SSR is mounted in.
I ran an animated deer on one channel last year without a problem. Realize that it was a small motor in parallel will lights, so your mileage may vary.
Zane...my understanding (in other words, I have not tested it) is that a snubberless TRIAC will work on a small inductive load without a snubber circuit.
I have been meaning to test this, but have not got around to it.
So, again, just my understanding, you can use the current layout of SSR, but install a snubberless TRIAC instead of the ones we are using, with no other changes.
Sean
I have been meaning to test this, but have not got around to it.
So, again, just my understanding, you can use the current layout of SSR, but install a snubberless TRIAC instead of the ones we are using, with no other changes.
Sean
wjohn
New member
http://labcontrol.pqui.utfsm.cl/~wally/Manuals/Power_Electronics/snnubers_necesary.pdf
good document on snubbers
good document on snubbers
The triac listed in the parts list is a non-sensitive gate triac, I poked around in the mouser catalog and found this snubberless triac. It should be a suitable replacement for the channels with inductive loads when using the coop board. This needs be verified by someone though.
511-BTA08-600BW
8)
511-BTA08-600BW
8)
The SSR that I'm using with my grinch board says its applications can be.
1. Isolated interface between high voltage AC devices
and lower voltage DC control circuitry.
2. Switching motors, fans, heaters, solenoids, and
valves.
3. Phase or power control in applications such as lighting
and temperature control equipment.
Its a Sharp S102S01 Series SSR in a 4 pin sip package only 4.13 from mouser.
1. Isolated interface between high voltage AC devices
and lower voltage DC control circuitry.
2. Switching motors, fans, heaters, solenoids, and
valves.
3. Phase or power control in applications such as lighting
and temperature control equipment.
Its a Sharp S102S01 Series SSR in a 4 pin sip package only 4.13 from mouser.