The EDI Model 510 solid state Load Switch is designed to meet all requirements of both the NEMA TS-1 and TS-2 Standards. The EDI Model 200 solid state Load Switch is designed to meet all requirements of Caltrans TSCES 1989. These specifications define minimum output load requirements of 10 Amps RMS (1200 watts) over the full NEMA temperature range of -34oC (-30oF) to +74oC (+165oF), in still air. In order to fully comply with all NEMA specifications including the 250 Amp single cycle surge test, the Model 510 and Model 200 use a triac device rated at 25 Amps.
The heavy duty extruded aluminum heat sink chassis of the Model 510 / Model 200 is designed to allow the triac device to operate with the full 10 Amp RMS load at high temperature (+74oC) without exceeding the manufacturer "Maximum Allowable Case Temperature" triac device specification. This helps ensure long life and reliable operation from the triac device. It can be shown that device reliability is logarithmically related to device operating temperature.
Tests were also conducted with the Model 510 / Model 200 Load Switch operating with a 15 Amp (1800 watt) load at +74oC in still air. The Model 510 / Model 200 operated correctly within NEMA specifications for the 24-hour continuous test with no damage to the test units observed.
It should be noted however that due to the additional power dissipated in the Load Switch with 15 Amp operation, adequate forced air cooling will be required in the cabinet to maintain the triac device within the manufacturer temperature specifications at this output load level. Operating the triac device beyond these specifications can directly affect performance and long term reliability.