Established in 1995 National Plastic Heater, Sensor and Controls' solid state relays (SSR's) and silicone controlled rectifier (SCR's) power controller products and services have been and continue to be at the leading edge of switching technology. NPH controls' products provide silent, reliable switching because of our unique application of solid state relays to heat sinks. Proper matching of heat sinks to SSRs and SCRs provides for long life, and a wide range of operating temperatures as well as higher reliability. NPH provides SSR assemblies up to 100 amps as well as SCR based power controllers up to 200 amps. For excellent quality, reliability, engineering and customer service, NPH should always be your first choice.
About Solid State Relays and SCR Power Controllers:
A solid state relay has a few major differences from an electromechanical one. SSRs have no moving parts and are extremely fast switching. SSRs are generally designed to turn on/off power when the line voltage crosses 0, so there is a smaller surge and no arcing which is a major problem with electromechanical relays that leads to their failure. Due to the fact that SSRs use semiconductor circuitry to switch the current, there is some heat that must be removed from the relay due to an internal voltage drop. This heat is removed through the heat sink that is appropriately sized for the load being switched. Heat sink design and application is one of NPHs' specialties and we have many innovative heat sink designs to solve this challenge. Since there are no moving parts and no arc, the expected lifecycle of a SSR is much greater that that of an electro mechanical model. With proper heat sink specification, billions of on/off cycles can be expected.
SCR's or silicone controlled rectifiers are switching devices for
electrical power and have no moving parts. These devices can switch
electrical loads within milliseconds and for millions of times. The
increased speed allows for choosing between zero cross switching
(also called zero-cross firing, burst firing or fast cycling) or
phase angle switching. Heater life will be greatly increased by
minimizing heater temperature fluctuations because of the less
contraction and expansion of the heating elements. Electromechanical
relays normally switch power every 10-20 sec. Shorter power
switching cycles will reduce the electromechanical relays life span.