This is a tricky one, and it's good you're being methodical in your troubleshooting. Given the symptoms and what you've tried, here's a breakdown of possible issues and what you might have considered (or could consider in the future if you encounter something similar)

Diagnosis & Considerations

1. Incorrect Internal Motor Configuration (MOST LIKELY)

The most probable explanation is that the internal configuration of the motor is not what the diagrams on the cover plate assume. Even if it's a standard 6-lead motor externally, the way the windings are connected internally at the factory could be different. This would explain why neither diagram worked. European motors often have 6 leads but can be wired as different pole arrangements.2.

Phase Sequence

While you tried two different wiring diagrams, it's less likely, but possible that the phase sequence of your power supply doesn't match the motor's intended direction. In that case, if you are using a VFD, switching any two output leads on the VFD can change the direction of rotation.3.

Motor Damage

It's possible the initial miswiring damaged the motor windings slightly, even if not visibly. This could result in the low RPM, rough running, and overload issues. You mentioned it overloads. That suggests excessive current draw, pointing to a winding problem.4.

VFD Settings

Ensure the VFD settings are appropriate for the motor. You mentioned it works with other motors, but double-check things like:

Motor Voltage

Is the VFD configured for the correct motor voltage?

Motor Current

Is the VFD configured for the motor's nameplate current?

Motor Frequency

(Usually 50Hz or 60Hz, depending on your location)

Motor Poles

Is the VFD configured with the correct number of poles? The number of poles can vary depending on the motor manufacturer. If you can't find the number of poles, you can figure it out by measuring the output frequency and RPM with a strobe tachometer.5.

Mechanical Binding

You checked without a belt, which is good. But double-check there's absolutely no mechanical obstruction inside the drum motor itself.6.

Wire Color Standards

While there are generally accepted color codes (like the ones you described), they are not absolute guarantees. Different manufacturers (especially across different regions) might deviate. Never rely solely on wire color.

Troubleshooting Steps (Considerations for Future Similar Problems)1. Complete Motor Nameplate Information

Document EVERYTHING from the motor's nameplate. This includes: Voltage rating (high/low) Current rating (high/low) Frequency RPM Number of poles (if listed) Motor type (e.g., induction motor) Manufacturing date (this can sometimes indicate design revisions) Manufacturer (obviously) and model numberThe model number is key to researching the motor and finding accurate diagrams.2.

Resistance Measurements (Ohmmeter)

This is crucial before applying power to any motor you suspect might be miswired. Measure the resistance between all possible pairs of the six leads: U1-V1, U1-W1, U1-W2, U1-U2, U1-V2 V1-W1, V1-W2, V1-U2, V1-V2 W1-W2, W1-U2, W1-V2 W2-U2, W2-V2 U2-V2The resistance values will give you clues about which windings are connected to each other internally. For example, if U1-U2 has a very low resistance, it suggests they are part of the same winding. Compare these values to what you'd expect based on a "typical" 6-lead motor configuration.. If there are any shorts to ground that will also appear on the ohm meter.3.

Megger Test (Insulation Resistance)

Use a megohmmeter (Megger) to test the insulation resistance between each winding and ground (the motor frame). A low reading indicates insulation breakdown, which could be contributing to the overload.4.

Detailed Photos

Take very clear, close-up photos of everything before you change anything. This includes the wiring, the terminal box, the nameplate, and anything else relevant.

Why the Service Rep Expected 9 Leads

The service rep's expectation of a 9-lead motor is important. 9-lead motors are designed to be wired as either dual-voltage Y or dual-voltage Delta, depending on the application. The fact that they expected it suggests there may have been a mix-up during the purchase process and the wrong motor got shipped.

Next Steps (Now that it's being returned)1. Insist on a Thorough Inspection

Make sure the manufacturer provides a detailed report of what they find inside the motor. Ask them to verify the internal wiring configuration and to explain why the diagrams on the cover plate were incorrect (if that's the case).2.

Verify the Replacement

When you receive the replacement motor, immediately verify that it matches the nameplate specifications and that it's indeed the correct model. Do the resistance measurements described above before attempting to wire it up.3.

Get a Correct Wiring Diagram: If the manufacturer admits there was a documentation error, demand a correct wiring diagram specific* to that motor's serial number (if possible).In summary, the problem is most likely an internal configuration issue or a motor winding problem. The systematic troubleshooting steps outlined above (especially the resistance measurements) can help you diagnose similar issues in the future. Good luck! Flag for review