Product range
Motor ratings shown for 400V three-phase. Confirm the exact frame against your motor nameplate and the required making capacity.
| Frame | Corrente nominal | Typical motor rating | Coil options | Use |
|---|---|---|---|---|
| SMO-K 09A-18A | 9A – 18A | 2.2 – 5.5 kW at 400V | 24V DC standard | Small motors, pumps, HVAC units |
| SMO-K 25A-38A | 25A – 38A | 7.5 – 11 kW at 400V | 24V DC standard | Machine tools, compressors, fans |
| SMO-K 40A-65A | 40A – 65A | 15 – 22 kW at 400V | 24V DC standard | Pumps, conveyors, mixers |
| SMO-K 80A-95A | 80A – 95A | 30 – 37 kW at 400V | 24V DC standard | HVAC plant, large fans, hoists |
| SMO-K 115A-150A | 115A – 150A | 45 – 55 kW at 400V | 24V DC standard | Heavy pumps, chillers, compressors |
Technical data
Values below apply across the SMO-K range. Confirm the exact rating for your frame size before ordering.
| Parâmetro | SMO-K value | Nota |
|---|---|---|
| Rated current (AC-3) | 9A – 150A | Across five frame sizes |
| Tensão nominal de funcionamento | Up to 690V AC | 50/60Hz |
| Rated control voltage | 24V DC standard | Other voltages on request |
| Number of poles | 3P | Other pole counts on request |
| Terminal type | Screw terminals | Solder and PCB variants available |
| Mechanical endurance | 1,000,000 cycles minimum | Tested per IEC |
| Short-circuit withstand (Icu) | 6 – 8 × rated current at 380V | Varies by frame size |
| Utilisation category | AC-3 | Also rated AC-1 |
| Contactos auxiliares | NO / NC, customer specified | Mirroring and interlock options |
| Reference standard | IEC 60947-4-1 | Routine-tested per batch |
Where we are
Morada
Chandong Village, Liushi Town, Yueqing City, Wenzhou, Zhejiang, China
Telefone
+86-18079491179
Sales email
helge@wzsmo.com
General enquiry
blackd@wzsmo.com
Moulding, coil winding, plating and testing all sit in the same industrial area. A revised spring or contact reaches us in days, not weeks, which is what makes small custom runs possible.
A frame you have not used before can be sent as a sample for bench testing and panel fit before the production order is placed, so the first bulk shipment is not the first time you see the part.
The person who answers the technical questions at quotation follows the batch through inspection and packing. Specifications do not get re-negotiated between departments. More background on the company is under about SMO Electric.
Send the frame size, coil voltage and quantity, and the quotation comes back with the model, the unit price and the lead time — usually the same working day, rather than after a week of internal forwarding.
Manufacturing and testing
Contacts, coils, springs and moulded cases are checked against the purchase specification before anything reaches assembly. A batch that does not match is rejected at the door rather than sorted out later on the bench.
Coil, armature, contacts and arc chambers are fitted, then the mechanism is set so the moving contact travels the designed distance under the spring force. Set too loose the contactor chatters; set too tight it will not pick up cleanly at low control voltage.
Every unit is energised and released to confirm it closes at the rated control voltage and opens when the coil is de-energised, without sticking and without contact bounce beyond tolerance.
A dielectric test is applied between the main poles and between the coil circuit and the main circuit. Contact resistance is measured at the same station, so a badly seated contact is caught here instead of in a panel on site.
Units that pass are packed with the routine test record and the packing list, marked with the frame size, coil voltage and batch. Units that fail are taken off the line for teardown, not adjusted and pushed back into the batch.
Visiting before shipment: Customers who want to see a routine test run on their own batch are welcome to attend before the shipment is released. The same checks are what catch the failures described in AC contactor troubleshooting.
Delivered projects
Standards and documentation
Project experience
We needed the same 40A frame on both 24V DC and 220V AC, with our own nameplate and packaging, shipped as two separate pallet sizes to two markets.
Distributor order pattern
Our panel builder asked for a specific terminal arrangement so the incoming cables land on the same screw positions across all five frames, which cut assembly time on site.
Panel builder order pattern
The routine test report was the part that mattered, because their customer audit required the breaking capacity to be documented per unit rather than per batch.
OEM order pattern
Coil voltage, rated current, number of poles, mounting method, whether you need auxiliary contacts, and the annual quantity. If you have a motor rating in kW, send that instead of the current and we will select the frame for you. A motor nameplate photo is usually enough for us to quote from.
Yes. We manufacture under customer brands, covering the unit finish, nameplate, packaging, manual and the certification documents. Minimum order quantity depends on the frame size and the level of customisation, and it is confirmed with the quotation rather than quoted as a fixed figure.
24V DC is our standard for panels because it allows the control circuit to share one supply with other 24V devices such as push buttons and indicator lamps. 220V and 380V AC coils are also available on request. If your panel already runs on 24V, specifying a DC coil avoids adding a separate control transformer.
AC-3 covers switching squirrel-cage motor loads and is the rating that matters for motor starters, because it covers both making and breaking the high inrush current a motor draws at start. AC-1 covers resistive or non-inductive loads with a much lower making capacity. Every SMO-K frame is rated AC-3, and the AC-3 figure is the one to check against your motor. Coil voltage and AC-3 rating goes through the numbers in more detail.
Auxiliary NO and NC contacts can be added on either side of the contactor to provide holding, interlock or status feedback. Specify the combination you need when ordering, for example 1NO + 1NC for a standard starter or 2NO for a reversing contactor pair. The full range sits under auxiliary contact blocks and accessories.
The routine test record and packing list go with the shipment, and a certificate of origin can be arranged for the destination market. If your customer audit needs a specific document set, tell us the country and the model before the order is placed, so the paperwork can be prepared before the goods leave the factory.
Lead time depends on the frame size, coil voltage and order quantity, and is confirmed with the quotation. Frames with standard coil voltages and no special branding are the shortest, while private-label units and non-standard coil voltages take longer because the nameplate and packaging are produced separately.
Yes. An SMO-K contactor is normally paired with a thermal overload relay in a motor starter, and the relay mounts directly on the contactor body. Give us the relay frame you plan to use with the quotation and we will confirm the mechanical fit for that frame size.
