What is a servo press?

A servo press uses servo motors for precise force and position control during forming operations.

How do I calculate servo press tonnage?

Use our free tonnage calculator at servopress.club/tonnage-calculator.html

Servo Motor Replacement on Press: Step-by-Step Procedure

admin

Replacing the servo motor on a press is a major maintenance job. Done correctly, the press is back in production the same day. Done incorrectly, you can damage the new motor or lose the press home position.

## Before You Start

Gather these items before beginning:
- Replacement motor (verify part number matches exactly, including encoder type)
- Motor parameter file backup (from the drive)
- Torque wrench calibrated for the motor mounting bolt spec
- Coupling alignment tools
- Dial indicator for coupling alignment
- New motor mounting bolts (do not reuse old bolts)

## Step 1: Back Up Drive Parameters

Before disconnecting anything, back up the drive parameters to a USB drive or laptop. If the drive loses power during the swap, you need these to restore the configuration.

Also record the current home position value from the drive display.

## Step 2: Disconnect Power

Lock out and tag out the main power. Wait for the DC bus to discharge (check the drive display - it should show 0V before proceeding). The DC bus on a servo drive can hold lethal voltage for several minutes after power is removed.

## Step 3: Disconnect the Motor

1. Disconnect the power cable at the motor terminal box
2. Disconnect the encoder cable at the motor connector
3. Label both cables before disconnecting
4. Remove the motor mounting bolts
5. Support the motor before removing the last bolt - servo motors are heavy

## Step 4: Install the New Motor

1. Clean the mounting surface
2. Install new motor, hand-tighten mounting bolts
3. Align the coupling: radial runout under 0.05mm, angular misalignment under 0.1 degrees
4. Torque mounting bolts to specification in a cross pattern
5. Connect encoder cable first, then power cable

## Step 5: Restore and Verify

1. Restore drive parameters from backup
2. Power on the drive and verify no alarms
3. Perform absolute encoder setup procedure
4. Re-establish home position
5. Jog the press through full stroke at 10% speed, verify smooth operation
6. Run 20 strokes at 50% speed, check motor temperature
7. Return to production speed, monitor for first 30 minutes

## Common Mistakes

- Not backing up parameters before starting
- Reusing old mounting bolts (they stretch and lose clamping force)
- Skipping coupling alignment (causes vibration and premature bearing failure)
- Not re-establishing home position (press will crash the die on first production stroke)

raj_maintenance

Done this 4 times now. The alignment step is the most critical and the most rushed. Use a dial indicator on the coupling and get runout below 0.02mm. I've seen shops eyeball the alignment and then wonder why the new motor runs hot. Misalignment causes bearing load that the motor isn't designed for.

anna_controls

After replacing the motor, always re-run the auto-tuning procedure on the drive. The new motor's characteristics will be slightly different from the old one (even same model number). On Yaskawa, run Fn005 auto-tuning. On Siemens, run the motor identification routine. Skip this and you'll get suboptimal performance or oscillation.