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Motor Brake Connections
For motors with spring set brakes, connect the brake power leads and the
motor power leads separately. Because the inverter has variable voltage
output to the motor, the inverter may not supply enough power at low
frequencies for proper brake operation. If using a motor with an internally
connected brake, the brake power leads must be connected to a separate
power source for proper brake operation. Refer to Figure 3-2 for terminal
locations.
Optional Dynamic Brake Hardware
Dynamic Brake (DB) Hardware must be installed on a flat, non-flammable,
vertical surface to obtain effective cooling and operation. The ambient
temperature must not exceed 80°C. DB connections are shown in Figure 3-6.
See
recommended
Tightening Torques in Section 6.
Note: Although not shown, metal conduit should be used to shield all power wires
and motor leads.
General Machinery Load Calculations:
1.
Calculate braking duty cycle:
2.
Calculate deceleration torque:
where:
3.
Calculate watts to be dissipated in dynamic braking resistor:
where:
4.
Multiply watts calculated in step 3 by 1.25 to allow for unanticipated
loads (safety factor).
MN715P
Figure 3-6 Wiring for RGA Assembly
J5
Power Terminal Strip
R1
Terminal
R2
Braking Time
Duty Cycle +
Total Cycle Time
RPM change
T
+
Decel
308
T
= Deceleration torque in lb-ft.
Decel
2
Wk
= Inertia in lb-ft
time = In seconds
Watts + T
S
Decel
S
= Speed to start braking
max
S
= Speed after braking
min
DB
Terminals
Optional
R1
Dynamic Brake
R2
Resistor
Wk
2
* Friction
(Lb.Ft.)
time
2
Duty Cycle
* S
max
min
( 0.0712 )
Receiving and Installation 3-8
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