Soid State Relay Voltage Resistance Regulator ?

[Maheel]

I am just looking at these SSR's

am i correct in thinking they use a POT to regulate the power let through the SSR therefore changing the final current allowing control over a heating element ?

http://www.ebay.com.au/itm/AC-24-380v-25A-...=item2eb8deb5dc


i have one of these phase angle controllers from RS (below) on a heating system (element) where i can regulate the power driving the element from +-1V up to +-240V using a pot therefore changing how quickly it comes to boil.

http://tiny.cc/7o8kr

just considering the ebay link as a cheaper option fr a 2nd one but was unsure of how they exactly work (how to drive the SSR on the ebay link )


thanks for your help

 

[Supra-Jim]

I think hsb is correct, or at least as far as I understand it. The reason for an SSR over a contactor in this application (coupled with a PiD controller) is that the SSR is better suited for a high switching rate (ON/OFF switching).

Cheers SJ

edit: hsb posted seems to have disappeared

 

[hsb]

Sorry, deleted my post to let a more authoritative response. I am no sparky!
But yes SSR is just a switch, use a PID.
I didnt know what the 2nd link was, hence the disappearing post.

 

[Maheel]

Sorry, deleted my post to let a more authoritative response. I am no sparky!
But yes SSR is just a switch, use a PID.
I didnt know what the 2nd link was, hence the disappearing post.

yeah i know what a SSR and PID is and do but this SSR and wording OHM / restrictive load etc appears to be different

 

[Jono_w]

yeah i know what a SSR and PID is and do but this SSR and wording OHM / restrictive load etc appears to be different

An SSR will apply full supply voltage say 230v while its input is on so to vary we pulse on and off using a pid at set intervals, A Phase Angle controller will chop the AC supply , this provides a constant reduced supply to the load proportional to the input resistance from say a potentiometer. As we are sealing with large volumes of water with good heat conductivity an SSR does the job fine as the liquid holds its temp smoothing out the on/ off periods of an SSR. Phase angle really only needed in my view with delicate materials where pulsing at low frequency could damage elements or heated media.

SSR - Much easier to interface with wide variety of PID controllers

Phase Angle - Smoother heating but more difficult to interface and also should have a RFI filter = more cost.

Cheers

 

[Maheel]

bump for the night crowd...

anyone got any info on the ssr in the ebay link "SSR Resistance Regulator"?

than ks

 

[Tony]

The SSR is the switch but how it switches the power is dependant on the input setup of the SSR.

I have on that i use for on/off control like a quiet contactor. It has a 240v input to switch it on and off, and the SS contact switches the high power side to the element.

The other type will use a 4-20mA input to the SSR to control how much power it puts out. The SSR will clip the AC waveform to control how much power goes to the element.

4mA will be no power, 20mA will be 100% power, and its a linear scale in between with 12mA being 50% power.

I just ordered one from here:

http://www.auberins.com/index.php?main_pag...6379b2c8a351e80

and a controller (with the SSR output to give me power putput control)

http://www.auberins.com/index.php?main_pag...6379b2c8a351e80


hope this helps

 

[spudfarmerboy]

The SSR is the switch but how it switches the power is dependant on the input setup of the SSR.

I have on that i use for on/off control like a quiet contactor. It has a 240v input to switch it on and off, and the SS contact switches the high power side to the element.

The other type will use a 4-20mA input to the SSR to control how much power it puts out. The SSR will clip the AC waveform to control how much power goes to the element.

4mA will be no power, 20mA will be 100% power, and its a linear scale in between with 12mA being 50% power.

I just ordered one from here:

http://www.auberins.com/index.php?main_pag...6379b2c8a351e80

and a controller (with the SSR output to give me power putput control)

http://www.auberins.com/index.php?main_pag...6379b2c8a351e80


hope this helps

Tony,
Which PID controller and SSR did you order and would they be any good for controlling a HERMS? Did the one you order use 4-20 mA control?
Cheers