High-performance motion control equipment can move rapidly with
very high forces. Unexpected motion may occur especially during
product commissioning. Keep clear of any operational machinery and
never touch them while they are working.
Keep clear of all exposed power terminals (motor, DC Bus, shunt, DC
power, transformer) when power is applied to the equipment. Follow
these safety guidelines:
•When using a separate logic supply, turn on the logic power supply
first before turning on the main power supply.
•Always turn off the main power and allow sufficient time for
complete discharge before making any connections to the drive.
•Do not rotate the motor shaft without power. The motor acts as a
generator and will charge up the power supply capacitors through
the drive. Excessive speeds may cause over-voltage breakdown in
the power output stage. Note that a drive having an internal power
converter that operates from the high voltage supply will become
operative.
•Do not short the motor leads at high motor speeds. When the motor is
shorted, its own generated voltage may produce a current flow as
high as 10 times the drive current. The short itself may not damage
the drive but may damage the motor. If the connection arcs or
opens while the motor is spinning rapidly, this high voltage pulse flows
back into the drive (due to stored energy in the motor inductance)
and may damage the drive.
•Do not make any connections to any internal circuitry. Only
connections to designated connectors are allowed.
•Do not make any connections to the drive while power is applied.
•Do not reverse the power supply leads! Severe damage will result!
•If using relays or other means to disconnect the motor leads, be sure
the drive is disabled before reconnecting the motor leads to the
drive. Connecting the motor leads to the drive while it is enabled can
generate extremely high voltage spikes which will damage the drive.
Use sufficient capacitance!
Pulse Width Modulation (PWM) drives require a capacitor on the high
voltage supply to store energy during the PWM switching process.
Insufficient power supply capacitance causes problems particularly with
high inductance motors. During braking much of the stored mechanical
energy is fed back into the power supply and charges its output
capacitor to a higher voltage. If the charge reaches the drive’s over-
voltage shutdown point, output current and braking will cease. At that
time energy stored in the motor inductance continues to flow through
diodes in the drive to further charge the power supply capacitance. The
voltage rise depends upon the power supply capacitance, motor
speed, and inductance.
MNDGDPIN-06 2
Safety / General Safety Overview
