What does Yaskawa A1000 oL1 Fault - Causes & Fix mean?

oL1 means motor overload: the drive's thermal protection tripped. Most often caused by too-heavy load or incorrect motor current settings.

How do I fix Yaskawa A1000 oL1 Fault - Causes & Fix?

Work through the step-by-step fix below. Start with the quick reset and the most common cause, then check the specific part this guide points to. Most fixes need only basic hand tools and the right replacement part.

Can I keep using my Yaskawa appliance with A1000 showing?

Usually not. Yaskawa appliances show this error when a part or safety circuit is out of range, so running it can stop the cycle or make the problem worse. Diagnose and clear the error before normal use.

What part is most commonly replaced for Yaskawa A1000 oL1 Fault - Causes & Fix?

The parts that most often fix Yaskawa A1000 oL1 Fault - Causes & Fix are listed in the parts section of this guide. Match the part to your exact model and serial number before you buy.

Is Yaskawa A1000 oL1 Fault - Causes & Fix a DIY repair or do I need a technician?

Many fixes are DIY-friendly with basic tools, such as door switches, drain pumps, water inlet valves, thermostats, heating elements, and filters. Sealed-system, refrigerant, gas, or high-voltage work should go to a licensed technician for safety.

Yaskawa A1000 oL1 Fault - Causes & Fix

Yaskawa A1000 oL1 Fault — What It Means

The oL1 fault on a Yaskawa A1000 drive is a motor overload trip. The drive’s electronic thermal protection has determined that the motor has accumulated too much heat from output current and has shut down to protect the motor from damage. This protection is based on an internal thermal model that estimates motor heating from current and operating time, not just a simple instantaneous current spike.

The fault will not reset until the overload condition is corrected and the internal overload value (parameter U4-16) drops below 100.0%. Simply resetting the fault without fixing the underlying cause will result in the same trip happening again, often very quickly.

Before You Replace Anything

Technicians sometimes replace the drive itself when oL1 appears, but this fault usually points to load, setup, or motor issues rather than a failed power section. Check motor parameters, acceleration times, and mechanical load before considering drive replacement.

Jump to Fix

Common Causes

Load too heavy (~35%) The driven equipment requires more torque than the motor and drive are sized to deliver, forcing sustained high current draw.
Motor-rated current set incorrectly (~25%) The drive’s motor current parameter does not match the motor nameplate, causing the thermal model to trip prematurely or too late.
Acceleration or deceleration too fast (~20%) Ramp times are too short, causing excessive current during starting or stopping.
Mechanical binding or misalignment (~10%) The driven equipment has excessive friction, gearbox problems, or misalignment that forces the motor to draw more current.
Long low-speed operation (~5%) Running at low speed with inadequate motor cooling raises motor temperature and increases overload risk.
Motor damage or overheating (~5%) The motor itself has winding damage, insulation breakdown, or has been overheated beyond recovery.

Quick Diagnosis

Answer these to narrow it down fast.

Does the drive display U4-16 at 100.0% or above?

Yes: The overload condition is still active. The fault cannot be cleared until this value drops below 100%. Stop the motor, allow it to cool, and verify the load is removed or reduced.
No: The overload value has dropped. You can reset the fault, but the underlying cause must still be fixed or the fault will return immediately.

Does the motor nameplate current match the value entered in the drive's motor parameter settings?

Yes: Motor current is programmed correctly. Focus on mechanical load, acceleration times, and motor condition.
No: Incorrect motor current parameter is likely causing false overload trips or inadequate protection. Program the correct nameplate current into the drive.

Can you rotate the driven load by hand with normal effort when the motor is off?

Yes: Mechanical load is likely acceptable. Check drive programming, motor cooling, and whether the load exceeds the motor's continuous rating.
No: Binding, misalignment, or seized bearings are forcing excessive current. Repair the mechanical system before restarting.

Step-by-Step Fix

Stop the motor immediately and do not attempt to reset the fault until the overload condition is corrected.
Check parameter U4-16 on the drive display to verify the overload value has dropped below 100.0% before attempting a reset.
Inspect the mechanical load for binding, misalignment, seized bearings, or gearbox problems by rotating the load by hand with the motor disconnected.
Verify motor nameplate data entered into the drive, especially the motor-rated current parameter, and correct any mismatch between nameplate and programming.
Review acceleration and deceleration times in the drive programming and increase ramp times if the overload occurs during starting or stopping.
Check motor ventilation and cooling, especially if the motor operates at low speed for extended periods, and make sure the motor is rated for the duty cycle.
Test the motor for winding damage using insulation resistance and continuity tests if the motor shows signs of overheating or if faults persist after correct setup.
Reset the fault only after fixing the cause, then monitor current draw and U4-16 during operation to confirm the overload does not return.

Parts Often Needed

Part	Notes
Replacement motor	Amazon \| Required if insulation resistance or continuity testing shows winding damage or overheating beyond recovery.
PG encoder or PG option card	Amazon \| Only needed if the application uses feedback and the overload is tied to speed-control issues.

When to Call a Pro

Call a qualified electrician or VFD technician for oL1 faults. Diagnosis requires understanding motor thermal models, programming drive parameters correctly, and testing motor windings with insulation resistance equipment. Mechanical load issues may need a millwright or machinery specialist. If you are not trained in variable-frequency drive programming and motor testing, professional help will save time and prevent damage to the motor or drive.

Rough cost: A pro service call runs about $200-600 depending on whether the fix is programming, motor replacement, or mechanical correction.