Siemens Drive Fault Code 7902 [better] Info

The most frequent culprit behind F7902 is human error during initial data entry. The drive utilizes these baseline numbers to scale its measurement pulses. If the numbers are wrong, the test fails.

Line 4 was the heart of the factory, a massive Siemens-driven servo press responsible for churning out the chassis plates for the new electric vehicle contract. If it was down, the morning shift would start with a disaster, and the plant manager would be breathing down everyone's necks before sunrise.

If you are running in without an encoder, check the monitoring parameters. siemens drive fault code 7902

The motor fails to restart after an OFF/ON cycle without p1200 (flying restart) enabled. 3. Step-by-Step Troubleshooting and Solutions

Disconnect the motor cable from the drive terminals (U2, V2, W2). Use a high-quality digital multimeter to measure the phase-to-phase resistance ( ). The resistances must be balanced and equal. The most frequent culprit behind F7902 is human

This fault triggers the drive’s built-in monitoring function, which compares the current in all three phases (U, V, W) at the drive’s output. If the current in one phase falls below a specific threshold relative to the others, the drive assumes a cable break or motor winding failure and shuts down to prevent damage.

A automotive paint line conveyor trips with F07902 every Monday morning but runs fine for the rest of the week. Line 4 was the heart of the factory,

The power unit cannot supply the required startup current. 3. Troubleshooting & Solutions (Step-by-Step) Follow these steps to diagnose and clear the fault: Re-commission Motor Data (Crucial): Perform a factory reset of the converter. Set p0010 = 1 (Quick commissioning). Enter exact motor nameplate parameters: Rated voltage ( ), current ( ), power ( ), Power Factor ( ), and speed ( Set p3900 = 3 (Quick commissioning for motor parameters).

G120XA solution to warning F7902 motor out of step - Siemens

When the internal speed adaptation controller output surpasses standard operation thresholds for longer than the set delay time, the drive determines that the rotor cannot keep up with the electrical field under its current load profile and drops into a fault state. Technical Mechanism: How F7902 is Triggered