Configuring a VFD for a Yaskawa 180 V Induction Motor

A VFD can control the three-phase Yaskawa UAX3EE-04DK2T if the drive can supply at least the motor’s 2.1 A nameplate current and its voltage/frequency profile is limited to the motor’s 180 V rating. The number that matters for drive sizing is output current, not only the 0.4 kW power rating. Confirm the rated frequency before commissioning: 1800 r/min motivates a 60 Hz hypothesis, but speed alone does not establish frequency because pole count and slip also affect shaft speed.

Nameplate quantities and operating limits

The unusual voltage is not a fault indication. It is a motor design value that must become an explicit point in the VFD’s motor data and volts-per-hertz configuration. This is heat, not logic: excessive magnetic flux raises magnetizing current, excessive load raises torque-producing current, and both increase winding temperature.

If 2.1 A is three-phase line current, the nameplate apparent-power calculation is sqrt(3) × 180 V × 2.1 A / 1000 = 0.655 kVA. Real input power cannot be calculated from those values without power factor, and shaft efficiency cannot be calculated without real input power.

Symptom interpretation

A drive that is configured for a conventional 220 V or 230 V motor can apply too much voltage at the motor’s rated frequency. For example, commanding 230 V where the motor requires 180 V raises commanded voltage by 27.8%. At the same frequency, that also raises the commanded V/Hz ratio by 27.8%, which can push the magnetic circuit toward saturation and produce high current with little useful increase in torque.

Separate this condition from load overload. High current at light load points toward incorrect motor data, an excessive V/Hz ratio, wiring trouble, or a motor fault. Current that rises mainly during acceleration or indexing points toward demanded torque, acceleration time, reflected inertia, mechanical binding, or an undersized drive. Current that remains acceptable while temperature climbs points toward excessive cycle duty, inadequate cooling, or operation at low speed where a shaft-mounted fan moves less air.

Volts-per-hertz and speed mechanism

An induction motor’s air-gap flux is governed primarily by voltage divided by frequency. A V/Hz drive therefore raises voltage with frequency up to the configured base point. Above the available voltage limit, frequency may continue rising while voltage cannot; flux and available torque then fall.

If documentation confirms that this motor is rated 180 V at 60 Hz, its nominal ratio is:

180 V / 60 Hz = 3.0 V/Hz

Maintaining that derived ratio would reach 230 V at:

230 V / 3.0 V/Hz = 76.7 Hz

That calculation identifies an electrical V/Hz point, not permission to run at 76.7 Hz. The motor’s maximum mechanical speed, rotor balance, bearing limits, indexer gearing, lubrication, and driven-load rating must all permit the resulting speed. A higher-frequency base point or extended constant-power range also requires motor documentation; the nameplate values alone provide no maximum-speed or constant-power rating.

VFD selection and configuration procedure

1. Read the complete motor nameplate and associated machine documentation. Record rated frequency, connection information, maximum speed, insulation or inverter-duty restrictions, ambient conditions, and the definition of 40% ED.
2. Select a VFD with a three-phase output suitable for the motor and a continuous output-current rating of at least 2.1 A. Check the drive’s overload curve against the indexer’s acceleration current and cycle duration; a matching kilowatt label does not prove adequate current capacity.
3. Verify that the VFD can produce the required 180 V output from the available supply. A drive cannot create arbitrary output voltage beyond the limit imposed by its DC bus and modulation range.
4. Enter the exact motor data available: 0.4 kW, 180 V, 2.1 A, and 1800 r/min. Enter rated frequency only after reading it from authoritative motor or machine data.
5. If rated frequency is confirmed as 60 Hz, configure the applicable motor or V/Hz base point as 180 V at 60 Hz. Use the drive manual to locate the corresponding parameters because no VFD model or parameter identifiers are specified here.
6. Set maximum frequency to a mechanically approved value. Leave operation above base frequency disabled until Yaskawa or the machine documentation supplies a permissible maximum speed and torque envelope.
7. Set acceleration and deceleration for the indexer’s inertia and braking arrangement. Lengthen acceleration if current limiting prevents the commanded speed ramp; address regenerative overvoltage during deceleration through the drive and machine’s specified braking method.
8. Configure electronic thermal protection from the 2.1 A motor rating and the documented duty cycle. Follow the selected VFD’s motor-tuning procedure only after entering correct nameplate data.

Commissioning verification

Begin uncoupled or at the lowest practical mechanical load when the machine permits it. Run at low frequency, confirm rotation, and observe all three output-current indications available from the drive. Then increase frequency in controlled steps while watching current, speed, vibration, and motor temperature.

At the confirmed rated operating point, compare displayed motor voltage, frequency, current, and speed with the configured values. The drive should not command more than 180 V at the motor’s rated frequency, and steady rated-condition current should not exceed 2.1 A. Short acceleration current must remain inside both the VFD overload envelope and the motor’s permitted intermittent-duty envelope.

Evaluate the real indexing cycle rather than a no-load continuous run. Calculate duty as ED = on-time / (on-time + off-time) × 100%, using the cycle definition supplied for this motor. The 40% ED marking does not specify the reference period, allowable starts, load profile, or cooling assumptions, so obtain those details before treating the percentage as a complete thermal rating.

Recurring configuration pitfalls

Frequently asked questions