3
PREFACE
Braking resistor unit and braking unit are used to con-sume regenerative 
energy from motor in the braking resistor unit at deceleration and to 
improve the transis-tor inverter braking ability. 
Before using the braking resistor unit and braking unit, a thorough under-
standing of this manual is recom-mended. This instruction manual will be 
of great help for daily maintenance, inspection and troubleshoot-ing. 
Inverters to which the braking resistor unit and braking unit can be con-
nected are of the following series:
•  YASKAWA AC Drive 1000 Series
•  Varispeed Series
Wiring sequence should shut off power to the drive when a braking 
resistor Overload Relay Trip Contact (Thermal Protector Contact) 
output is triggered.