YASKAWA P7, User Manual, Page: 40 / 256

Electrical Installation 2 - 12
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Dynamic Braking Connections
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General
Dynamic braking (DB) enables the motor to be brought to a smooth and rapid stop. This is achieved by dissipating the
regenerative energy of the AC motor across the resistive components of the Dynamic Braking option. For further details on
dynamic braking operation, see the instruction sheet shipped with dynamic braking components.
Drives P7U20P4 thru P7U2018 and P7U40P4 thru P7U4018 have an integral braking transistor and require the addition of a
Remote Mounted Resistor Unit or a Heat Sink Mount Resistor (ERF). All higher rated Drives require the use of a Braking
Transistor Unit (CDBR) and a Remote Mount Resistor Unit.
Remote Mount Resistor Units typically mount outside of the electrical enclosure. Braking Transistor Units mount inside of the
electrical enclosure. Heat Sink Mount Resistors mount to the back of the Drive, attaching directly to the heat sink.
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Installation
This option should only be installed by a technically qualified individual who is familiar with this type of equipment and the
hazards involved.
Hazardous voltages can cause severe injury or death. Lock all power sources feeding the Drive in the “OFF” position.
Failure to follow these installation steps may cause equipment damage or personal injury.
Preliminary Procedures
1. Disconnect all electrical power to the Drive.
2. Remove Drive front cover.
3. Use a voltmeter to verify that voltage is disconnected from incoming power terminals and that the DC bus has dissipated.
Table 2.7 Heat Sink Mount Dynamic Braking Resistor - 3% Duty Cycle
Drive Heat Sink Mount Resistor
Rated
Input
Vac
Drive
Model No.
P7U
Part No.
Qty.
Reqd.
Resistance
(Ohms)
Power
(Watts)
Approx.
Braking
Torque
(%)
Dimensions (Inches)
Height Width Depth
208-240
20P4 R7505 1 200 150 220 7.16 1.73 0.51
20P7 R7505 1 200 150 125 7.16 1.73 0.51
21P5 R7504 1 100 150 125 7.16 1.73 0.51
22P2 R7503 1 70 150 120 7.16 1.73 0.51
23P7 R7510 1 62 150 100 7.16 1.73 0.51
480
40P4 R7508 1 750 150 230 7.16 1.73 0.51
40P7 R7508 1 750 150 130 7.16 1.73 0.51
41P5 R7507 1 400 150 125 7.16 1.73 0.51
42P2 R7506 1 115 150 115 7.16 1.73 0.51
43P7 R7505 1 200 150 110 7.16 1.73 0.51
WARNING