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Limiting a 5500 watt heater
Posted: Wed Jun 27, 2018 3:49 am
by mal4545
I am building a new 5500 watt heater element (I already have one 5500 done and working properly) however due to my current circumstances it will be plugged into a 240v/20 amp socket (to be upgraded later to 30). Is there a way to limit the SSR-VA to a maximum draw of 15 amps so that I don't trip the breaker? Effectively putting a limiter on the potentiometer?
My SSR VA is KYOTTO AC Solid State Relay SSR KR2040AX 280VAC 40A with a 500k pot.
Thanks for the help.
Re: Limiting a 5500 watt heater
Posted: Wed Jun 27, 2018 4:16 am
by jonnys_spirit
Don’t turn the pot up all the way. You could use a 250k pot or less. That’s a 40A SSR.
Cheers!
-j
Re: Limiting a 5500 watt heater
Posted: Wed Jun 27, 2018 5:02 am
by StillerBoy
+1 on JS post
You should be ok to go to 3500 watts on the 20amp breaker.. if you have a meter on your controller, 14/15amp reading, if not use an amp meter to pin point the range and mark the pot location..
Mars
Re: Limiting a 5500 watt heater
Posted: Wed Jun 27, 2018 5:36 am
by mal4545
Thanks for the replies however I am not planning on putting a meter on the controller - trying to keep this as simple as possible. Also, I may not even put a pot on there to begin with, simply having it on/off to bring up to temperature faster and then controlling with my other element.
Regarding the 250k pot - I thought this would only limit the resolution and that fully open on the pot gives full power.
Really hoping there is a simple way to put a limiter in somewhere.
Re: Limiting a 5500 watt heater
Posted: Wed Jun 27, 2018 7:21 am
by jonnys_spirit
If you're POT is at the 1/2 way mark and it's then making the SSR operate @ 1/2 capacity then it should be at a resistance of 250k (assuming it's a linear potentiometer).
They're cheap so get 1 100k, a 200k, etc... See what works best for you.
You could put a fixed resister in there too if you want simple ON/OFF capability but I'd use a pot and add the ammeter too. It's just an inductor coil and a little additional components to have the measurement confidence.
I see that the Amps change too as the element settles into a certain power output value when you adjust... That's because at different operating temps and values the resistance on the element changes slightly and the current then also changes in tandem.
Cheers!
-j
Re: Limiting a 5500 watt heater
Posted: Wed Jun 27, 2018 8:45 am
by StillerBoy
mal4545 wrote:however I am not planning on putting a meter on the controller
Without a amp meter in the system, you are looking for potential problems.. as JS stated, adjusting the pot at the half way marks may not give you the reading you want because on a single pot a slight move one way or the other off the half mark with give a difference of 2 or 3 amps on a 5500 watt element.. and that could potentially create a draw higher than the breaker its on.. an amp meter are not expense, less than 10 dollars on ebay, and are easy to install..
Mars
Re: Limiting a 5500 watt heater
Posted: Wed Jun 27, 2018 10:40 am
by mal4545
Sounds like the pot is the way to go. Thanks for the help.
Re: Limiting a 5500 watt heater
Posted: Fri Jun 29, 2018 5:27 pm
by zapata
1/2 way on mine is not half power. I would use a meter. I think mine was like $10 and maybe added 5 minutes to the install. 15 minutes of you count finding a tool to make a cutout for it.