Q.I want to use an induction motor for bidirectional operation. How should I wire it?

A.

Induction motors are available in 2 types: three-phase power supply input type and single-phase power supply input type.
The wiring method differs depending on the power supply voltage.

[Three-Phase Power Supply Input Type]
A three-phase induction motor will rotate in the opposite direction if any 2 wires R, S, or T in Figure ① are switched.
Instantaneous bidirectional operation places a heavy load on the gearheads, which can damage them and reduce their lifetime.

Three-Phase Power Supply Input Type
Figure ①
*Main Products of Three-Phase Power Supply Input Type:
KIIS Series
Refer to here for a concept video of the connection.

[Single-Phase Power Supply Input Type]
There are 2 types of single-phase induction motors: those with 3 lead wires and those with 4 lead wires.
If you have 3 lead wires, you can easily rotate it in the opposite direction by switching the white and red wires on the L side, as shown in Figure ②.
When reversing a 4-lead wire induction motor, you can do so by swapping the black and white wires.
Therefore, connect the wires as shown in Figure ③.
If the load inertia of a single-phase induction motor is too great, the rotation direction will not switch when instantaneous bidirectional operation is performed.
Change the rotation direction only after a motor standstill.
If you want to perform instantaneous bi-directional operation while the machine is rotating, use a reversible motor.

  • In the video below, you can see the movement of a single-phase induction motor and a reversible motor when the rotation direction is switched during operation.
  • Single-Phase Power Supply Input Type  3 Lead Wires
    Figure ② 3 Lead Wires
  • Single-Phase Power Supply Input Type  4 Lead Wires
    Figure ③ 4 Lead Wires
*Main Products of Single-Phase Power Supply Input Type:
3 Lead Wires KII Series, World K Series
Refer to here for a concept video of the connection.
4-lead wires K Series

Product Category: AC Motors
Model and Series: Induction Motors
Description: Wiring method, Usage and Setting method
FAQ No.: 32


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