Notes On Power Transmission Mechanism - YASKAWA GA700 Technical Manual

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Explosion-Proof Motors
The motor and the drive must be tested together to be certified as explosion-proof. The same is true even for
existing installations of explosion-proof motors. The drive is not designed for explosion-proof areas. Ensure that
the drive is installed in a safe location.
The encoder used with pressure-resistant explosion-proof motors is intrinsically safe. When wiring between the
drive and encoder, always connect through a specialized pulse coupler.
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Geared Motors
The continuous speed range differs depending on the lubricating method and the manufacturer. In particular, in the
case of oil lubrication, continuous operation in the low speed range may cause burnout. Consult with the
manufacturer for the applications that require frequencies in excess of the rated frequency.
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Single-Phase Motors
Variable speed drives are not designed to operate with single phase motors. Using capacitors to start the motor
causes a high frequency current to flow to the capacitors and can damage the capacitors. A split-phase start or a
repulsion start can burn out the starter coils because the internal centrifugal switch is not activated. The drive is
for use with three-phase motors only.
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Motor with Brake
When using a drive to operate a motor with brake, and the brake is connected to the output side of the drive, it
may not release at start due to low voltage levels. Use a motor with brake that has an independent source of power
for the brake. Connect the brake power supply to the power supply side of the drive. Note that motors with built-
in brakes tend to generate a fair amount of noise when running at low speeds.
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Notes on Power Transmission Mechanism

Take care if continuously operating power transmission machinery at low speed, if such machinery incorporates
gearboxes, transmissions, or reduction gears that use oil for lubrication. At low speeds, oil lubrication systems can
lose their effectiveness. Note also that operation at a frequency exceeding the rated frequency can result in a
variety of problems with the power transmission mechanism, including audible noise and reduced service life and
durability due to centrifugal force. Due caution should be observed.
YASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual
2.25 Motor Application Precautions
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