| Inverter capacity selection |
When driving multiple motors in series with one inverter, select the inverter capacity so that 1.1 times the motors' rated current is less than the inverter's rated output current. Moreover, if a large starting torque is required, select an inverter capacity one rank higher. |
| Wiring |
Applying power to the U, V, and W output terminals of the inverter will damage the inverter block. Prior to applying power, carefully check that there are no wiring errors. |
| Installation location and operating environment |
Install the inverter in a well-ventilated indoor location away from direct sunlight, avoiding locations that have high temperature, humidity, or where condensation can easily occur, as well as locations with flying lint or dust, corrosive gas, grinding fluid mist or a salty atmosphere. When housing an inverter into a controller, establish a cooling method and controller dimensions such that the inverter's ambient temperature remains within the allowable range. If the inverter's ambient temperature exceeds +30°C or +40°C, the ventilation cover must be removed. Also, the surface of the inverter and the dynamic braking resistors reach high temperatures due to the operating conditions, so mount them on incombustible materials. |
| Maintenance and inspections |
Even if the inverter's power supply is shut off, the internal capacitors take time to discharge, so perform maintenance and inspections only after the charge lamp has gone out. Since residual voltage remains in the capacitors, they present a risk of electric shock. |
| Control circuit wiring distance |
To perform remote control operation, keep the wiring distance with the inverter within 20 m, and use a twisted-pair shielded wire for wiring. To prevent inductance from peripheral devices, perform wiring away from heavy-current circuits (main circuit and relay sequence circuit). |
Wiring length between
inverter and motor |
If the wiring to the motor is long, the inverter may overheat due to the high-frequency current that flows as stray capacitance between the wires on each phase, and an overcurrent trip may occur. Set the carrier frequency to 50 m if Cd051 = 130 or less, 100 m if Cd051 = 090 or less, and 200 m or less if Cd051 = 040 or less. |
| Wire size |
If the wiring distance between the inverter and motor is long (particularly during low-frequency output), the motor torque will decline due to the declining cable voltage, so perform wiring with a sufficiently thick wire. |
| Grounding |
Be sure to ground the inverter, using the grounding terminal. |
| Installation of circuit breakers for wiring |
Install a wiring circuit breaker (MCCB) for wiring protection on the inverter's input side.
Use a harmonic-resistant leak breaker. |
Application of input side
electromagnetic contactor |
Do not perform high-frequency opening/closing (more than once per hour) using the input-side electromagnetic contactor (MC), as this may damage the inverter. If high-frequency starting/stopping is required, do so through control terminal signal input. |
| Application of output side electromagnetic contactor |
As a rule, provide an electromagnetic contactor between the inverter and motor, and do not perform ON/OFF switching during operation. If an electromagnetic contactor has been provided on the inverter output side for switching to a commercial power supply, etc., use it when the inverter and motor are stopped. |
| Elimination of phase advance capacitor to improve power factor |
Power factor improvement capacitors on the inverter input side are not effective, so do not install them. Perform inverter power factor improvement with an AC reactor or a DC reactor. Also, do not insert power factor improvement capacitors on the inverter's output side, as this would cause overcurrent trips and prevent operation. |
| Installation of thermal relay |
The inverter has an electrothermal protection function, but when driving multiple motors with one inverter, install a thermal relay for each motor. |
| Radio disturbance (high-frequency noise) countermeasures |
The inverter's main circuit I/O includes harmonic components that may damage communication equipment, radios, and sensors used near the inverter. Such damage can be minimized by installing a noise filter. Using metal pipes for wiring between the inverter and motor and on the power supply side, and grounding these metal pipes, is also effective. |
| Insulating voltage |
When using a 400 V type motor with a voltage-type PWM inverter that uses IGBT, insulation degradation of the motor coil may occur due to surge voltage caused, for example, by the cable length. Consider using a motor with reinforced insulation. |
| Temperature rise |
When driving a general-purpose motor with an inverter, the temperature will rise to be slightly higher than during operation with a commercial power supply. Moreover, the cooling effect in the low-speed range is reduced, so the allowable output torque is lower. Therefore, use a motor provided with a power-operated ventilation fan. |
| Vibrations |
Resonance may occur due to a natural vibration frequency, including the mechanical section. Providing vibration damping rubber pads or an inverter frequency jump function is effective. |
| Noise |
When operating a general-purpose motor with an inverter, the noise level is higher than during operation using a commercial power supply. For noise reduction, set a high carrier frequency for the inverter. Also, wind noise becomes prominent during high-speed operation at 60 Hz or higher. |
| Geared motors |
The continuous use rotation range differs according to the lubrication method and the manufacturer. (Particular care is required for the low-frequency range for the oil lubrication method.) |
| Brake motors |
Use a brake motor with an independent brake power supply. Connect the brake power supply to the inverter's primary power supply and switch off the inverter output using the free-run command (MBS allocation to multifunctional input terminal) during brake operation (motor stopped). |
| Submersible motors |
Submersible pumps Since the rated current for these motors is larger than for general-purpose motors, when choosing an inverter, select one with a suitable inverter capacity, based on the motor's rated current. |
| Explosion-proof motors |
When driving an explosion-proof motor, it is necessary to use an inverter and motor combination that has been tested for explosion-proof characteristics. |
| Synchronous motors |
Since design is frequently performed in specifications that best suit the type of motor, consult Sanken Electric when selecting an inverter. |
| Single-phase motors |
Since single-phase motors are not suitable for variable speed operation via an inverter, use a three-phase motor instead. |
