37
External Power Supply Units
IMS-MN-LMDE42C_A
Liberty MDrive Ethernet TCP/IP
External Power Supply Units
DANGER
ELECTRIC SHOCK CAUSED BY INCORRECT POWER SUPPLY UNIT
• Use a DC power supply unit that meets voltage requirements.
• Connect the negative output of the power supply unit to PE (ground).
Failure to follow these instructions will result in death or serious injury.
When working on power supply wiring and inserting or removing power connectors, it may
cause unintended behavior and possible destruction of the system components.
GENERAL POWER SUPPLY PRACTICES
• Disconnect the primary side of the power supply to power down the DC supply.
• Do not connect or disconnect the power supply while power is applied.
• For battery operated systems, connect a “transient suppressor” across power switches to
prevent arcs and high-voltage spikes.
Main Power VVDC
General
The power supply unit must be rated for the power requirements of the drive. The supply
voltage and current can be found in the technical data.
Actual power requirements are often significantly lower since the maximum possible motor
torque is usually not required for normal operation of a system.
When designing the system, note that the input current of the drive is higher during the motor
acceleration phase than during constant movement.
Regeneration Condition
Note the following for drives with large external mass moments of inertia or for highly dynamic
applications:
Motors return regeneration energy during deceleration or back driving/overhauling load.
The DC bus can store a limited amount of energy in the capacitors. Connecting additional
capacitors to the DC bus increases the amount of energy that can be stored.
If the capacity of the capacitors is exceeded, the excess energy must be discharged via an
external braking resistor controller. If the application of the drive generates a regeneration
condition, contact a member of the IMS Applications department for additional information at:
.
Overvoltage conditions can be limited by adding a braking resistor with a corresponding
braking resistor controller. This converts the regenerated energy to heat energy during
deceleration.
