3-6
3.5
Precautions for wiring work
Warning
Use high-quality wiring equipment and devices, and carry out wiring work
safely and securely according to the technical standards for electrical
facilities, as well as the indoor wiring regulations.
Only qualified personnel such as licensed electrical engineers are
allowed to carry out electric wiring work.
Unqualified persons are prohibited by law from performing wiring work.
Caution
Check that the supply voltage and frequency are suitable for the motor.
3.5.1. Power cable
Warning
Be sure to install a ground fault interrupter exclusively for this equipment
at the primary power supply. Otherwise, an electric shock and/or fire may
occur.
Warning
Be sure to attach a ground wire to the motor, and be sure to perform
grounding work.
Warning
Connecting a ground wire to gas or water pipes is illegal and extremely
dangerous.
Caution
Securely tighten the power cable connection terminal.
A loose terminal may lead to open-phase operation and damage the
motor.
(1) Be sure to install a ground fault interrupter and an overload protection device on the primary power side
of the pump.
(2) Be sure to attach a ground wire to prevent an electric shock. Connect the ground wire to the ground
terminal in the terminal box of the motor.
(3) Put the power cable in a metal pipe or metal duct to shield it, and ground the outer surface of the pipe.
(4) Keep power voltage fluctuations within the range of ±10% of the rated voltage, and frequency
fluctuations within the range from +3% to -5% of the rated value. The use of the equipment beyond
these limits may cause a failure. Even if they are within the allowable ranges of fluctuations, the pump
characteristics, motor characteristics, temperature rises, etc. are different from the rated values.
(If the power voltage is lower than the rated voltage, any fluctuations may cause an overload even
within the range of specified flow rates.)
(5) Precautions for inverter driving
(5-1) Ensure to keep the operation current value within 90% of the rated current value.
(5-2) Ensure to keep the operation frequency within 95% to 50% of the commercial power frequency.
(5-3) Do not perform the inverter driving of the motor with a self-protection device.
(5-4) The pump and the piping system may vibrate sympathetically at a certain operation frequency.
Avoid operation at a frequency that leads to significant vibration.
(5-5) In the case of inverter driving, magnetic noise occurs from the motor, and may sounds noisy in
comparison with commercial power driving. This magnetic noise does not adversely affect the
quality of the motor. The noise tone can be adjusted by changing the carrier frequency depending
on the inverter. However, if the carrier frequency is changed, the allowable output of the inverter
may be reduced. Therefore, be careful when selecting an inverter.
