120V Smart Dimmer to control zero cross SSR

Thread Starter

bdlooze

Joined Apr 17, 2024
1
Hello,

I am building a control panel for a set of infrared heaters and would like to use some smart dimmers that use leading edge dimming with 120v (https://inovelli.com/collections/in...r-white-series-smart-2-1-on-off-dimmer-switch).

Because these cannot be directly used with the heaters, I would like to use some solid state relays to control the heat. There is a specific Infratech SSR (Carlo Gavazzi, but specially made for 0-120v dimming for Infratech) that allows 0-120v control. It's based on their RM1E SSRs (https://www.digikey.com/en/products/detail/RM1E23V50/1864-2754-ND/9520357).

Is there something that I would be missing using a leading edge type dimmer instead of a typical analog dimmer?

Thanks!
 

MisterBill2

Joined Jan 23, 2018
18,934
Is there a reason to not use duty cycle control for the heaters? And the expression "Leading edge dimmer" is a bit unclear. But that will not work well with zero-crossing switching relays. And what is the anticipated benefit from using "smart" dimmers?? My experience with "Smart" devices is tha they usually try to be smarter than they should be and add extensive time requirements to making a system work as it should. Phase control, as provided by dimmers that delay conduction at the start of a phase using a triac, are not likely to work correctly with most SSR devices, which are intended to provide ON/OFF control similar to a mechanical relay. So the response time may or not be adequate.

What sort of IR heaters are to be controlled? Do you mean the IR LAMP BULBS?? or the resistance wire heated radiant types? That matters .
 
Last edited:

kaindub

Joined Oct 28, 2019
132
As MisterBill 2 said, heater control is usually done by burst control not phase control. Thats because of the slow time constant of a heating system.
 

OldTech

Joined Jul 24, 2009
10
Is there a reason to not use duty cycle control for the heaters? And the expression "Leading edge dimmer" is a bit unclear. But that will not work well with zero-crossing switching relays. And what is the anticipated benefit from using "smart" dimmers?? My experience with "Smart" devices is tha they usually try to be smarter than they should be and add extensive time requirements to making a system work as it should. Phase control, as provided by dimmers that delay conduction at the start of a phase using a triac, are not likely to work correctly with most SSR devices, which are intended to provide ON/OFF control similar to a mechanical relay. So the response time may or not be adequate.

What sort of IR heaters are to be controlled? Do you mean the IR LAMP BULBS?? or the resistance wire heated radiant types? That matters .
I Think the proper term for "leading edge dimming" that the OP mentions is more properly described as "Integral Cycle Power Control". Google search returns a fair list of sites to visit that fully describes the technology.
I have used this type of contol for a couple of soldering iron controllers. Much lower power than the OP's heater, but the
 

OldTech

Joined Jul 24, 2009
10
I think the proper term for "leading edge dimming" that the OP mentions is more properly described as "Integral Cycle Power Control". A Google search returns a fair list of sites to visit that fully describes the technology.
I have used this type of contol for a couple of soldering iron controllers. Much lower power than the OP's heater, but the circuitry remains the same, the only difference would be the power capacity of the SCRs or Triac used to control the load. Some example web pages:

https://www.ijser.org/researchpaper...cle-Power-Control-for-Welding-Application.pdf
https://www.renesas.com/us/en/document/apn/1164-cycle-stealing-control
https://schematicsforfree.com/files...ower Information/Full Cycle AC Controller.pdf (I used a variation of this circuit for my soldering iron controllers).
https://www.microchip.com/en-us/application-notes/an958 If you want to build a copy of this example, I have the PIC code that I can send you).

I have a few other articles & circuits that I investigated that I can send if you're interested.
Hope that helped.
Cheers,
DaveM
 

Ian0

Joined Aug 7, 2020
10,001
Leading-edge dimming, is where the leading edge is modulated. i.e. standard phase-fired triac dimming. The power is switched on at some point during the cycle and switches off at the end of the cycle.
Trailing-edge dimming is where the trailing edge is modulated. i.e. the power is switched on at the beginning of the cycle and off a variable time during the cycle. Much more complicated, because you can't do it with a triac.

Leading edge causes more interference. Both have bad harmonics.
For anything that doesn't cause visible flicker, proportional control where a the power is on for a given number of full cycles in a frame is preferable, unless it has a really short (<20ms) thermal time constant.
 
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