JVL MAC050 - Page 108

104 JVL A/S - User Manual - Integrated Servo Motors MAC050 - 4500
3.2 Power Supply
3.2.27 Connecting an external power dump resistor
The internal power dump can absorb up to 9W continuously and 2.5kW peak, which is
considered as appropriate for most applications.
However should a situation occur in which the connected load inertia is too large or the
deceleration too fast, the internal power dump will not be able to absorb all the returned
energy and will report the error message “regenerative overload”.
In this situation the only possible solutions are as follows:
1. Decrease the acceleration/deceleration parameter.
2. Lower the attached load inertia.
3. Connect an external power resistor.
The drawing above shows how to connect an external power resistor. A wirewound
type is recommended since it will be able to absorb higher peak power than other types
of resistors. A wirewound resistor with the value 33 Ohm or 47 Ohm is the optimum.
Warnings: Ensure that the resistor value is not lower than 33 Ohm since the output
can be damaged. Also avoid short-circuit of the output.
MAC800/1200
L1
N
PE (Earth)
PE (Earth)
PD
BO
CM
MAC800/1200 with external power dump connection.
TT1013-03GB
Vel ocity
Time
Time
Time
Vol ta ge (V)
BO-PD (V)
R
33 to 68 Ohm
100W Wirewound
Nom. 325VDC
400V
Energy fed back from
the motor to the DC bus
PD activated
when voltage
exceeds 400V
Shielding/housing must
be connected to earth
Main earth.
Always make sure that
the motor is connected
to earth.
Note ! : Its only necessary to
connect screen to signal source.
Connector box for power and power dump.
Screen
Common. Is internally connected to the ground of the DC bus.
Is only intended to be used if multiple motors share DC-bus.
Bus output. The internal DC bus is connected to this terminal.
Power Dump output. Behind this terminal is placed a switch
(IGBT transistor) which connect the terminal to the internal
bus ground if the voltage become higher than 400VDC.
Terminal description for the “Dump” connector.
CM =
BO =
PD =
CAUTION - Risk of electric
shock. Disconnect all power and
wait 5 min. before servicing