Power — Transformer size in KVA

Once the voltage is determined, the power required at peak load (heat-up) can be calculated by use of the following formula:

Power (KVA):

Total Resistance X 1000

Total Resistance:

Length of Band (cm) X
Band Resistance (Ohms/cm)


Maximum allowable KVA for RES-Controllers:
at 400 volt primary power supply is 8.0 KVA
at 230 volt primary power supply is 4.4 KVA
at 115 volt primary power supply is 2.2 KVA

Applications that require more power can be operated by use of a Booster System. Please look under "Accessories" or contact the JBE Application Engineering Staff for assistance.


The transformer’s secondary voltage selection is very important because the controller will go full “ON” when the controller is first activated. If the secondary voltage is too low, the ramp-up will be slow and the time required to reach the pre-set temperature will be too long. Alternatively, if the voltage is too high, the ramp-up rate may exceed 1°C/mSec. In this case, the controller will go into a switching mode, control will be unsatisfactory, and damage to the controller may result.


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