Two 5500 watt 240v heating elements not heating up.

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doug293cz

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Are the relays actually contactors and not mechanical relays? The later can't handle the fast switching of a digital controller. Not sure if they aren't heating at all or just getting warm.
Contactors ARE mechanical relays. And in this (and almost every other controller) design the element isolation contactors are not being driven by the PLC's PID. The PID controls switching of the SSRs, which are what actually modulate power to the elements. The contactors/relays are used to enable/disable power to the elements by providing galvanic isolation.

Also, the OP has diagnosed the issue as faulty structure wiring in the circuit that was supposed to provide power to the controller. Essentially the controller wasn't completely "plugged in."

Brew on :mug:
 

Wolffie

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That left main bus bar in the breaker panel looks like it has broken loose of its moorings. It may not be making contact with the back of the breaker. This could be the cause of your problem. I'd look into this first. The breaker itself seems to be connected correctly. But, this is not a GFCI breaker, and you really want GFCI for your own protection. Regular breakers just protect the wiring from overload - they do nothing to protect you.

The wire connections at the "outlet" box look like they are correct. However, it is my understanding that the National Electrical Code (NEC) no longer allows appliances to be hard wired to the structure wiring. Technically what you are doing is a "no-no."

Brew on :mug:
And The wizard strikes again ! Nice job Doug :bigmug:
 

Bobby_M

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Are the relays actually contactors and not mechanical relays? The later can't handle the fast switching of a digital controller. Not sure if they aren't heating at all or just getting warm.
Contactors are mechanical relays. The Solid State Relays (SSRS) are the fast switching ones. Both are in that box. SSRs are under the control of the PID or micro computer and the mechanical relays are under the control of the brewer. Oops.. I forgot to refresh the page and have been redundant.
 

RufusBrewer

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Terminology can be confusing. A conventional relay uses a coil that when energized creates a magnetic field that pulls one of more electrical contacts closed. These contacts might have a normally closed and normally open and a common combination terminals.

A contractor is very similar to a relay. Both use a coil that pulls the switch contacts together. I have never seen a reliable definition of what makes a contactor different than a conventional relay. From what I can tell, contractors tend to be for higher power and mostly normally open.

Key point is a relay and contracter both use coils and a mechanical switch that you can see and hear.

Solid state relays use transistors other solid state elements to switch their signals. They have no moving parts. The switching element is "fast". That means you can switch it on and off many times a second. (relays you do not want to turn them on and off very often)

Solid state relays the switch section has only two terminals, they are either On/closed (passing current) or Off/open (not passing current)

Solid state relays have a wide range of input signal. A few volts up to about 30 volts DC. Depends on relay design and specifications.

One tricky part about SSR, you cannot put a meter on the switch terminals, apply a signal to the input and observe the switch close. A meter across the switch terminals will not show a change on the meter. You must put an active load, to see the observe the relay change state.

With solid state relays, cooling and heat management is an issue. They can generate heat when used, and that heat needs to be dissapted.
 
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