106 models · 6 manufacturers
Soft Starters repair
Reduced-voltage starters for pumps, compressors, fans and crushers. Soft starters are simpler than drives, but they work hard: every start pushes high current through the thyristors. Most faults are in the power section, the bypass contactor or the control card.
Manufacturers
Soft Starters by manufacturer
Models
Soft Starters in the catalog
A selection. Pick a manufacturer above for the full list, or search by part number at the top of the catalog.
| Model / part | Manufacturer | Actions |
|---|---|---|
| ATS48C14QStarter, soft altistart 48 model | Telemecanique | |
| ATS48C25QStarter, 132Kw soft altistart 48 model | Telemecanique | |
| ATS48C32QStarter, soft altistart 48 model | Telemecanique | |
| DTC 01/2018Card, kit module - SOFT START assembly | Danfoss | |
| SIRIUS 5L3SOFT starter 3RW4073-6BB44 | Siemens | |
| STARTER 3RW3047-1BB14Sirius SOFT | Siemens | |
| STARTER 3RW4055-6BB44AC semiconductor motor | Siemens | |
| STARTER 3RW4074-2BB44AC semiconductor motor | Siemens | |
| STARTER 3RW4434-6BC44Sirius SOFT | Siemens | |
| STARTER 3RW5076-6BB44Sirius SOFT | Siemens | |
| STARTER ALTISTART-48 ATS48C14YS316SOFT | Telemecanique | |
| STARTER ALTISTART-48 ATS48C32QSOFT | Telemecanique | |
| STARTER PSE370-600-70SOFT | ABB | |
| STARTER PSE85-600-70SOFT | ABB | |
| STARTER PST142-600-70Of SOFT control card | ABB | |
| STARTER SMC-3Low voltage SOFT | Allen-Bradley |
- ATS48C14QStarter, soft altistart 48 model · Telemecanique
- ATS48C25QStarter, 132Kw soft altistart 48 model · Telemecanique
- ATS48C32QStarter, soft altistart 48 model · Telemecanique
- DTC 01/2018Card, kit module - SOFT START assembly · Danfoss
- SIRIUS 5L3SOFT starter 3RW4073-6BB44 · Siemens
- STARTER 3RW3047-1BB14Sirius SOFT · Siemens
- STARTER 3RW4055-6BB44AC semiconductor motor · Siemens
- STARTER 3RW4074-2BB44AC semiconductor motor · Siemens
- STARTER 3RW4434-6BC44Sirius SOFT · Siemens
- STARTER 3RW5076-6BB44Sirius SOFT · Siemens
- STARTER ALTISTART-48 ATS48C14YS316SOFT · Telemecanique
- STARTER ALTISTART-48 ATS48C32QSOFT · Telemecanique
- STARTER PSE370-600-70SOFT · ABB
- STARTER PSE85-600-70SOFT · ABB
- STARTER PST142-600-70Of SOFT control card · ABB
- STARTER SMC-3Low voltage SOFT · Allen-Bradley
Common faults
What usually fails on Soft Starters
Shorted thyristors
A shorted thyristor makes the motor start direct-on-line or trips the starter on a phase fault.
Bypass contactor or relay wear
Worn bypass contacts overheat once the motor is up to speed, causing thermal trips after the start.
Overheating from frequent starts
Starts per hour above the rating, or blocked cooling, cause thermal trips and long-term thyristor damage.
Control card faults
A dead display, no start command response or wrong current readings point to the control electronics.
Phase loss and imbalance trips
Often the supply or motor, but sometimes the starter's own current sensing.
First checks
What to check before calling an engineer
Isolate and lock out the supply, and wait for stored energy to discharge, before opening anything.
Safe for plant staff
- Note the trip message and whether it happens during or after the start.
- Measure supply voltage on all phases.
- Count starts per hour against the starter's rating.
Leave to a specialist
- Testing thyristors and the bypass circuit.
- Adjusting current limit and ramp settings for a heavy load.
- Any work inside the starter with the supply connected.
Warranty. Repairs carry a warranty of 30 days to 6 months, depending on the item and the repair; the exact term is confirmed before work starts.
FAQ
Soft Starters repair questions
Why does the soft starter trip only after the motor reaches speed?+
That usually points to the bypass contactor or its control, or to heat building up in the starter. Both are checked during the repair.
More manufacturers
Soft Starters from other manufacturers
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