Wiring Of Contactors - Mitsubishi MELDAS MDS-C1 Instruction Manual

2-7 Wiring of contactors

A contactor (magnetic contactor) is inserted in the main circuit power supply input (L1, L2, L3) of a
power supply unit, and the power supply input is shut off when an emergency stop or servo alarm
occurs.
When an emergency stop or servo alarm occurs, the servo drive unit stops the motor using deceleration
control or a dynamic brake. The spindle drive unit performs the deceleration stop control. The power
supply unit must maintain the power supply (power regeneration) while returning the energy from each
axis being decelerated to the power line. Thus, the contactor cannot be shut off. Therefore, the NC
controls the contactors. The NC confirms that all axes are stopped, or confirms the dynamic brake
operation, and then it outputs a contactor shutoff command of the power supply unit via the drive unit.
Give consideration to the above, and examine the contactor drive method in the following order of
priority.
CAUTION
2. Wiring and Connection
1. The contactors cannot be driven other than from a power supply unit.
Undervoltage (alarm) may occur if the contactors are shut off at the same
time as an emergency stop occurrence.
2. Do not directly shut off the contactors with an external sequence. They may
shut off faster than the emergency stop input, and the input power supply
may be shut off during the deceleration control or vertical axis drop
prevention control. If this happens, an undervoltage alarm will occur, and
deceleration control or drop hold may not be possible. When
double-protecting, use a drive unit external emergency stop input.
(Refer to section "2-9 Wiring of an external emergency stop.)
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