Diagnostic workflow

Siemens 6SE70 KTY/PTC Motor Temperature Diagnostic

Entry symptom: MASTERDRIVES reports motor-temperature warning/trip or inconsistent KTY/PTC sensor behaviour.

Protection diagnostic workflow8 min read

Scope of this technical record

Step-by-step route for 6SE70 KTY/PTC motor-temperature warnings, separating sensor-route faults from true motor overheating.

Safety boundary

Do not bypass thermal protection. Any powered check must preserve motor and process safety.

6SE70 motor-temperature workflow route

1Sensor identity
2Timing
3Wiring
4Cooling
5Configuration

The workflow separates cold-start sensor faults from real load-related heating.

6SE70 motor-temperature workflow image

6SE70 motor temperature workflow sensor identity timing wiring cooling configuration
The workflow image separates cold-start sensor problems from load-related heating.

Workflow sequence

The workflow starts by identifying the sensor and classifying timing. Cold motor faults generally move toward wiring, terminals and configuration; load-related faults move toward fan, airflow, bearing, duty cycle and motor heating evidence.

After the physical sensor route is proven, configured warning/fault behaviour can be reviewed. Configuration is not a substitute for a working protective circuit.

Thermal diagnostic workflow

StepEvidenceDecision
1KTY84 or PTC identifiedCorrect test method
2Cold versus hot timingSensor route or true heating
3Motor terminal and cable evidenceWiring/connection boundary
4Cooling and motor conditionReal overtemperature boundary
5Configured responseWarning/trip handling after physical proof

Field record checklist

  • Sensor type
  • Timing
  • Terminal photos
  • Continuity/resistance evidence where appropriate
  • Cooling/fan state
  • Configured response

Technical basis and reference documents

This is an independent editorial technical reference. Original manufacturer documentation remains controlling for installation, repair and commissioning decisions.

SIMOVERT MASTERDRIVES Vector Control Operating InstructionsSiemens Industry Support

OEM basis for 6SE70 / 6SE71 safety, control connections, motor temperature evaluation and option context.

SIMOVERT MASTERDRIVES brake and thermal protection evidence notesIndustrialDriveData editorial extraction

Internal technician note set used only to structure public diagnostic routes around KTY/PTC thermal protection and brake-control evidence.

Linked records

Evidence intake

Turn this record into a qualified service request

A repair decision is much more reliable when the request includes the exact identity of the drive, the first fault evidence and the machine condition when the symptom appeared.

  • Complete drive type code / MLFB or nameplate model
  • Fault code, fault value and first event before reset
  • When the event appears: power-up, enable, ramp, run, decel or stop
  • Motor/cable connected or isolated during the symptom
  • Visible board, option-card, module and connector identifiers
  • Previous repair history, replacement parts and repeat-failure pattern
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