Quiet Drive Solid State
Evenheat's Quiet Drive Solid State Relay System does away with the mechanical relays traditionally used in kilns and replaces them with solid state relays.
Traditional, mechanical relays wear out and fail at some point. They have to and they always will. Not so with the solid state. Solid state means there are no moving parts, nothing to wear out and nothing to replace.
Our Quiet Drive Solid State Relay System delivers tight temperature control, long life and desired heating element response. The Quiet Drive is arguably the best designed and best performing solid state system on the market.
Evenheat's Quiet Drive Solid State Relay System is available as an option on all Evenheat models except for the Studio Pro STP.
First of all - What's a Relay Anyway?
A relay is basically a switch. In the case of a kiln, it's the switch that turns the heating elements on and off to control chamber temperature.
Traditionally, kilns have used mechanical relays for temperature control. Mechanical relays, in their most basic form, contain a set of metal contacts that physically open and close and a magnetic coil that makes that happen. These parts move and electrically arc during the operation of the relay.
Solid State Relays, in their most basic form, contain a semiconductor which is a solid block of material. There are no moving parts or electrical arcing in a solid state relay.
While each style of relay essentially does the same thing; solid state offers some great advantages over the mechanical design.
Quiet Drive Advantage - Longer Relay Life
Mechanical relays physically move and electrically arc as they operate. If you're familiar with a traditional kiln or oven, the "clicking" sound you hear are the mechanical relays operating.
It's not unheard of to have a mechanical relay turn on and off a thousand times during a firing. This constant On/Off causes wear, especially with electrical arcing seen at the switch contacts. At some point the mechanical relay simply wears out and fails.
Solid state relays have no moving parts and run silent, hence our term "Quiet Drive". Mechanical wear or arcing does not exist with a solid state relay.
Evenheat fully expects our solid state relays to last the life of the kiln or oven, and so far they have since their introduction in 2016!
Quiet Drive Advantage - Tight Temperature Control
There is a limit to how frequently a mechanical relay can or should be operated. For the kiln manufacturer this is a balancing act between good control and relay life but is generally limited to no more than one cycle every 10 seconds. While this works, very tight temperature control can only be achieved if we drastically shorten this time.
A solid state relay operates at 120 times per second, as needed. This control resolution, if we can call it that, is measured in milli-seconds rather than multiple-seconds and presents a great opportunity for the control to make very quick heating decisions resulting in very tight temperature control.
All of our controls are designed to take advantage of the solid state's fast operating capability.
Quiet Drive Advantage - Longer Heating Element Life
Heating elements are powered from the AC power line. AC is alternating and therefore the voltage becomes 0V 120 times every second (North America). Heating elements absolutely love to be turned on and off at 0V and they show this love by lasting longer.
So what does this have to do with the relay?
Mechanical relays have no clue what the line voltage is, ever. They turn on and off without any timing or feedback from the line voltage. What this means is that the mechanical relay does nothing to help extend heating element life. They would if they could, but they can't, so they don't.
Solid state relays on the other hand, can be selected to turn on and off only when the line voltage is at 0V. This is called "Zero Crossing". The solid state relays we have selected are designed this way. Heating element life is extended with this Zero Crossing feature.
Better by Design - 30A Rated
We've chosen solid state relays that are rated for 30 amps while limiting the actual current we run through them to 15 amps. We're basically running our solid state's at half of their full capacity. Why? Headroom!
Our goal is to provide a solid state system that works well and continues to work well into the future. Our 30 amp solid state's run very cool with a 15 amp load; well below the derating curve for proper operation.
Better by Design - Externally Mounted Heatsinks
Solid state relays get warm as they operate and require airflow for proper cooling. We mount our solid state relay heatsinks externally to provide unrestricted airflow and prevent heat build-up.
Better by Design - Conclusion
We believe we have created the ultimate solid state relay operating environment and less than a handful of failures since 2016 confirms that.
Better by Design in all we do.