Electrical data

Continuous duty

The data of the outputs for our electric motors are generally referred to S1 continuous duty. At this duty cycle, the motor can operate continuously at constant load as it reaches the thermal stability. Different duties are indicated in the tables inside the motors catalogues.

Nominal output

The outputs of Soga electric motors refer to the nominal output expressed in kW, that is the output power supplied by the motor to the shaft.

Frequency and voltage

All the technical data described refer to motors supplied at 50Hz. Our electric motors are available in single and three-phase version. IEC EN 60034-1 admits a voltage variation of ±5% with a maximum increase of temperature rise of 10°C.

Efficiency classes

Soga three-phase electric motors are available in standard single speed three-phase version and IE3 version in compliance with IEC 60034-30 defining IE efficiency classes (International Efficiency) for single speed squirrel cage three-phase asynchronous motors with outputs from 0,75 kW to 375 kW, voltage up to 1000V and continuous duty operation.


Motors in execution 2, 4, 6, 8 poles for extra EU markets or for EU markets used in applications not requiring high efficiency, operating in S6 75% duty.


Motors realized by Soga in 2 and 4 pole execution from 0,75 kW. They offer a high premium efficiency by ensuring a strong decrease in electricity consumption, allowing to recover the investment from the first year of use.

Thanks to their design optimized for high efficiency, IE3 motors ensure the windings a much lower thermal stress than motors with IE1 standard efficiency, allowing a longer motor life.

For IE3 models, executions different from the standard 50Hz may change variations in the efficiency levels.

60Hz use

The standard frequency for Soga motors is 50Hz. Standard three-phase motors can also operate at 60Hz. On request we can manufacture motors with special voltage.

Insulation classes

Soga single and three-phase motors in standard execution are Class F insulated. IE3 premium efficiency motors are Class F insulated with temperature rise Class B. Motors in Class H are available on request.

Windings treatment and post-treatments systems

Primary processes applied on stator windings for Soga motors are the following:

  1. Impregnation by dip with water-based varnish: treatment for single-phase and three-phase motors up to size EC132. Windings are dipped in an open tank containing water-based varnish (single-component).
  2. Impregnation by dip with polyester resin: treatment for three-phase  motors from size IEC132 up to IEC200. Windings are dipped in an open tank containing insulating polyester resin (single-component) while an active and constant check of the temperature is also applied.
  3. VPI vacuum encapsulation with epoxy resin: it is a treatment on request. The epoxy resin (single-component) is applied in autoclave through VPI (Vacuum Pressure Impregnation) system in aim to eliminate any moisture, air and gas in the windings. It is suitable for high voltage applications.
  4. Vacuum encapsulation with bi-component resin: treatment on request through epoxy bi-component resin, recommended for rotating electrical machines used in extreme contexts and, more generally, when the priority is to ensure the highest reliability level of the windings, for instance in automotive, wind and railway industry.

Always on request, on windings which have been previously impregnated, it is possible to apply tropicalization process on stators as a post-treatment, when the motors are used in high moisture (>95%) and saline environments (marine applications).

As a special execution we can also supply windings with UL1446 insulation system.

Use with inverter

The standard series of our motors starting from size IEC112 is suitable for use with inverter, being equipped with phase separators on the end windings.

Motors with this execution can also be realized on sizes below IEC112, on request.


Each motor is tested directly in our production lines. Our testing room and staff are available to customers who want or need to do further tests on custom-made motors manufactured by Soga, for applications requiring this such as railway.

Motor plates

Soga motors are equipped with metal plates or stickers describing the main electrical data.

serie MM1, MMD1, MME1

serie MT1

serie MT3

SOGA reserves the right to implement, update and change the data without prior notice