ω Start
ω Stop
∆t
∆ω/∆t
175ZA863.11
Illustration 2.16 Decelerating Servo Drive
The peak power connected to line 1 can be calculated as:
Ppeak ISD line 1 = PPeak ISD 1.1 + PPeak ISD 1.2 + PPeak ISD 1.n + . . .
The calculation for line 2 can be done in the same way.
The maximum peak brake power is the sum of the peak
brake power on both lines when the result is a negative
value.
Ppeak brake = PPeak ISD line 1 + PPeak ISD line 2
With P
peak brake
, the optimal resistance value can be
calculated using the formula for brake resistance.
Calculation of brake resistor average power
The average power is determined by the length of the
braking time in relation to the process period.
P
[W]
P
peak
P
avg
T
p
T
b
t [s]
175ZA094.13
T
p
Process period time in s.
T
b
Braking time in s.
Illustration 2.17 Relation between Average Power and Peak
Power
The average power is calculated as follows:
Pave = Ppeak x
Tp
Tb
The duty cycle is calculated as follows:
Duty cycle [%]
=
Tp x 100
Tb
Danfoss offers brake resistors with a duty cycle of
maximum 10% and 40%. If a 10% duty cycle is applied, the
brake resistors are able to absorb P
peak
for 10% of the
period time. The remaining 90% of the period is used on
deflecting excess heat.
2.11.2 External Encoder and Sensors
2.11.2.1 External Encoder
An external encoder can be connected to the X4
connector on the advanced servo drive or the encoder
connector on the SAB. The encoder value can be used as
guide value provider.
Further information on external encoders and sensors can
be found in the
VLT
®
Integrated Servo Drive ISD
®
510
Operating Instructions
.
2.11.2.2 Sensor
The M12 I/O and/or encoder connector (X4) is available of
the advanced servo drive. See
for pin assignment.
System Overview
VLT
®
Integrated Servo Drive ISD
®
510 System
28
Danfoss A/S © 08/2017 All rights reserved.
MG36C102
2
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