Temp controllers

Oldman · September 20, 2005, 11:55:28 AM

mrdennisg,

Much Thanks for the links. I really liked that last one and the way it was set up.

Olds

mrdennisg · September 20, 2005, 03:51:00 PM

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by bubbagump
 car54,

I noticed the specs. for the temp. controller you are using list the output relay as having a 3 amp. rating. Is that correct? The BS on high would draw approx. 4.2 amps.

Bubbagump
<hr height="1" noshade id="quote"></blockquote id="quote">

You can always up the power that a relay uses by using a contactor as I did in my controler spec's.my relay maxed out at 10 amps I nneded 25..... Working on another project now that calls for more than 50 amps and intend to use a relay that only puts out 10 amps (which are there max) to operate the 50 amp contactor

bubbagump · September 20, 2005, 09:00:03 PM

<blockquote id="quote">quote:<hr height="1" noshade id="quote">You can always up the power that a relay uses by using a contactor<hr height="1" noshade id="quote"></blockquote id="quote">

I guess that's my point. If in fact the relay output of the PID is only rated for 3 amps. I would not put directly in series with the heater. I would use a second relay with higher rated contacts, which would be controlled by the relay output of the PID.

Bubbagump

car54 · September 20, 2005, 09:59:44 PM

bubbagump,

You are right on the 3 amps. For some reason I thought it was more.But I used it for a 27 hour cook with no problems. I know other people have used the same controller with no reported problems. I was concerned about the controller getting too hot but the temperature gain did not seem to be much.

Brad

Oldman · September 21, 2005, 12:30:27 AM

Hmmmm I thought I read that one of the members here tested his bradley and it only used 2.7 amps.....

Olds

bubbagump · September 21, 2005, 01:10:23 AM

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Hmmmm I thought I read that one of the members here tested his bradley and it only used 2.7 amps.....<hr height="1" noshade id="quote"></blockquote id="quote">

Olds,

He must have been testing it on the 240 volt model. Nameplate rating on the 120 volt model is 625 watts and 5.2 amps. 4.2 amps is being drawn by the 500 watt heating element in the smoker box and the remaining 1 amp. is drawn by 125 watt smoke generator heating element. The 240 volt model should draw roughly half the amperage of the 120.

Car54,

Although the unit is working fine, you will have increased contact wear in the relay, which means shorter life. A lot depends on how often the load (heater) is cycled on and off by the controller. The opening and closing of the contacts (which creates an arc) is what causes contact erosion and is an inherent characteristic of electromechanical relays. But using contacts that are not rated for the load they are switching will increase the rate at which they wear.

Bubbagump

car54 · September 21, 2005, 01:31:39 AM

bubbagump,

I understand what you are saying. With this controller there is ALOT of relay action. I will probably install a secondary relay.

Brad

Arcs_n_Sparks · September 21, 2005, 02:22:39 AM

Car54,

Agree with Bubbagump; this is relay abuse with shortened lifetime. Time for a contactor. Especially since this PID controller is using on/off control with (as you point out) associated cycle rates for the relay.

Arcs_n_Sparks