Resistor braking
183
Verifying the capacity of the braking equipment
1. Calculate the maximum power
(P
max
) generated by the motor during braking.
2. Ensure the following condition is met:
The
P
brmax
values specified in the technical data table above are for the reference braking cycle
(1 minute of braking, 9 minutes of rest). If the actual duty cycle does not correspond to the reference
cycle, the maximum allowed braking power
P
br
must be used instead. In the technical data table,
P
br
is given for two additional braking cycles. See below for directions for calculating
P
br
for other
braking cycles.
3. Check the resistors selection. The energy generated by the motor during a 400-
second period must not exceed the heat dissipation capacity
E
R
.
If the
E
R
value is not sufficient, it is possible to use a four-resistor assembly in which two standard
resistors are connected in parallel, two in series. The
E
R
value of the four-resistor assembly is four
times the value specified for the standard resistor.
Custom resistors
Resistors other than the standard resistors can be used provided that:
• the resistance is not lower than with the standard resistors
WARNING!
Never use a brake resistor with a resistance below the value specified
for the particular drive / brake chopper / resistor combination. The drive and the
chopper are not able to handle the overcurrent caused by the low resistance.
• the resistance does not restrict the braking capacity needed, i.e.,
where
• the heat dissipation capacity
(E
R
) of the resistors is sufficient for the application
(see step 3 above).
P
max
maximum power generated by the motor during braking
U
DC
voltage over the resistor during braking, e.g.,
1.35 · 1.2 · 415 VDC (when supply voltage is 380 to 415 VAC),
1.35 · 1.2 · 500 VDC. (when supply voltage is 440 to 500 VAC) or
1.35 · 1.2 · 690 VDC (when supply voltage is 525 to 690 VAC).
R
resistor resistance (ohm)
P
brmax
>
P
max
P
max <
U
DC
R
2
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
Summary of Contents for ACS800-07-0610-3
Page 4: ...Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Page 7: ...Update Notice 3 Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Page 10: ...Update Notice 6 Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...