21619

Check Drive Parameter Configuration

Navigate to SINAMICS Startdrive or HMI Function 'Drive' → 'Parameters' → 'Safety/Monitoring'. Verify P0601 (temperature sensor type) matches installed sensor: 0=none, 1=PTC, 2=KTY84-130, 3=KTY84-150. Check P0604 (min temp) and P0605 (max temp) values are appropriate for sensor type.

KTY84-130 typically uses P0604=-40°C and P0605=155°C, while PTC sensors use different thresholds

Measure Sensor Resistance at Motor Terminal Box

Power down system and LOTO. At motor terminal box, disconnect temperature sensor wires (typically marked T1/T2 or TH1/TH2). Using calibrated multimeter, measure resistance across sensor terminals. KTY84 should read ~1000Ω at 25°C, PTC should read <1500Ω when cold.

Ensure motor is cool before testing - hot motor will show elevated but valid resistance

Test Sensor Wiring Continuity

With sensor disconnected at motor, measure continuity from drive terminal X21 pins (consult drive manual for exact pins) to motor terminal box sensor connections. Resistance should be <5Ω per conductor. Check for shorts between sensor wires and ground/other conductors.

Use TDR (Time Domain Reflectometer) on long cable runs to locate exact fault position

Replace Faulty Components

If sensor reads open/short, replace motor temperature sensor following motor manufacturer procedures. If wiring shows faults, repair/replace temperature sensor cable. After replacement, clear alarm via HMI 'Alarms' → 'Reset' and verify P0604-P0606 parameters show valid temperature readings.

Check Current Motor Temperature Reading

In SINAMICS Startdrive or HMI, navigate to 'Commissioning' → 'Motor Data' → 'Temperature Monitoring'. Check r0035 (motor temperature actual value) and compare to P0605 (temperature alarm threshold). Verify r0037 (temperature sensor resistance) shows plausible value for current temperature.

r0035 showing >130°C indicates genuine overheating condition requiring immediate investigation

Analyze Motor Loading and Thermal Model

Check r0031 (motor current actual) against P0305 (rated motor current). Verify P0335 (motor cooling type): 0=self-cooled, 1=forced air, 2=liquid cooled. Review r0034 (motor thermal load) - values >100% indicate overload condition. Check P0612 (thermal time constant) matches motor specifications.

Operating above 100% thermal load will cause cumulative motor damage even if temperature hasn't peaked yet

Inspect Motor Cooling System

Verify motor cooling fan operation (if equipped), check air intake filters for blockage, ensure adequate clearance around motor for air circulation. For liquid-cooled motors, verify coolant flow and temperature. Check motor mounting and coupling alignment to eliminate mechanical binding.

Use thermal imaging camera to identify hot spots on motor housing indicating internal issues or cooling problems

Adjust Drive Parameters for Thermal Protection

If overheating persists, reduce P0640 (maximum output frequency) or implement thermal derating via P0615 (thermal overload warning threshold). Consider enabling P0610 (motor temperature monitoring) with appropriate response in P0611 (temperature monitoring response).

Verify Physical Sensor Type on Motor

Check motor nameplate and documentation to identify actual temperature sensor installed. Common types: KTY84-130 (1000Ω@25°C), KTY84-150, PTC thermistor (typically 1000Ω@25°C but different curve), or Pt100 RTD. Note sensor part number if visible on sensor body.

KTY84 sensors have linear positive temperature coefficient, while PTC sensors have sharp resistance increase at trip temperature

Correct P0601 Temperature Sensor Type Parameter

In SINAMICS Startdrive, navigate to 'Expert' → 'Drive' → 'Motor temperature monitoring'. Set P0601: 0=No sensor, 1=PTC, 2=KTY84-130, 3=KTY84-150, 4=KTY84-131, 20=Pt100. Match exactly to physical sensor installed on motor.

Changing P0601 requires drive restart (P0970) to take effect - plan for controlled shutdown

Verify Associated Temperature Parameters

After correcting P0601, verify P0604 (minimum temperature for monitoring) and P0605 (maximum temperature alarm threshold) automatically updated to appropriate values for selected sensor type. Check P0606 (temperature warning threshold) is set below P0605.

P0604/P0605 values should auto-populate based on P0601 selection, but verify against motor manufacturer specifications

Test and Validate Configuration

Perform drive restart via P0970=1. Monitor r0035 (motor temperature) and r0037 (sensor resistance) for plausible readings. Clear alarm 21619 and verify stable temperature monitoring during normal operation. Document correct parameters for future reference.

Inspect Temperature Sensor Cable Routing

Trace temperature sensor cable from motor terminal box to drive terminal X21. Check for physical damage, excessive bending near motor (heat damage), cable ties too tight, or routing near high-current power cables causing EMI. Verify cable meets minimum bend radius specifications.

Temperature sensor cables should be routed separately from power cables and use twisted pair with shield connected to drive ground

Test Connection Resistance Under Movement

With drive powered down, connect multimeter to measure sensor circuit resistance while manually flexing cable at suspected problem areas. Look for resistance changes >10Ω during flexing. Pay special attention to cable entry points at motor and drive terminals.

Intermittent connections may only show up during thermal cycling or vibration - test when motor is at operating temperature

Check Terminal Connections and Crimps

Inspect all temperature sensor terminal connections at motor terminal box and drive terminal X21. Look for corrosion, loose screws, or degraded crimp connections. Re-torque terminals per manufacturer specifications. Check for moisture ingress in motor terminal box.

Use dielectric grease on outdoor installations and ensure proper IP rating sealing on all connections

Replace or Reroute Temperature Sensor Cable

If cable degradation found, replace entire temperature sensor cable with appropriate type (typically 2-conductor twisted pair, 300V rated, temperature rated for application). Ensure proper EMI separation from power cables and secure strain relief at both ends.

Verify Drive Internal Diagnostics

Access SINAMICS diagnostic buffer via Startdrive 'Commissioning' → 'Service' → 'Diagnostic buffer'. Look for related internal faults (21xxx series alarms) or A/D converter errors. Check r0949 (diagnostic buffer) for historical temperature-related faults.

Multiple simultaneous temperature alarms across different axes often indicate drive-level hardware issues rather than motor problems

Test with Known Good Temperature Sensor

Temporarily connect a known good motor with verified temperature sensor to the suspect drive channel. If alarm 21619 persists with good sensor, this confirms drive internal fault. Alternatively, connect suspect motor to different drive channel if available.

Ensure motor ratings match drive channel capabilities before connecting test motor

Check Drive Firmware and Parameter Corruption

Verify drive firmware version in r0018 against latest available from Siemens. Perform parameter backup and compare critical temperature monitoring parameters (P0601, P0604-P0606) against commissioning documentation. Look for parameter corruption indicators.

Parameter corruption often affects multiple related parameters simultaneously - check entire temperature monitoring parameter group

Escalate for Drive Hardware Replacement

If drive internal fault confirmed, document all diagnostic findings and contact Siemens technical support or authorized service center. Prepare for drive module replacement and parameter restoration from backup. Plan for extended downtime during hardware replacement.