4.5 Regenerative Resistor Selection48■ External Regen Resistors(1) If the power resistor is used at the rated load rate, resistor temperatures will reach 200°C~300°C. Be sure toderate before using. Check with the manufacturer for the load characteristics of the resistor. Use at a load ratingof 20% or less when using natural cooling (natural convection cooling), and at 50% or less when forced aircooling is used.(2) For safety reasons, we recommend the use of resistors with thermostatic switches.■ For Digital Torque Amplifiers of 400W Capacity or LessSGDG-01GTThe SGDG-01GT does not have the regen transistor built-in even though there areterminals for connecting an external regen resistor. Therefore, for external regenrequirement, the JUSP-RG08D external regen unit must be used. This unit connectsdirectly across the DC bus. It is a self-contained unit consisting of bus sensing circuitry,switching IGBT, 50 ohm power resistor, and alarm relay contacts. The regen capacity ofthis unit is 60W before derating. The convection cool capacity is 12W. Capacityincreases to 30W with forced-air cooling.When this external regen unit is used, #5 of SW1 in the SGDG-01GT should be turnedOFF to avoid erroneous alarms.The following is the dimension and specifications of the JUSP-RG08D:Dimensional DrawingsImportant
