Selection of Starters
Motor starters have two basic forms of operation: either automatic or manual.

Manaual starters are generally more economic but less versatile and normally only suitable for infrequent starting of smaller motors.

Automatic starters are rated for frequent duty, high mechanical durability and electrical life with the facility for remote control. Eaton MEMs comprehensive range of starters, covers the vast majority of motor starting applications up to 90kW.

Eaton MEMs Specials Department is equipped to provide additional types for special applications - e.g. two-speed d.o.l. starters for dual wound and tap wound motors; single-phase series parallel and split-phase starters; plus numerous varients on standard catalogue items to special order.

Single-Phase or Three-Phase?
The motor rating plate will tell you whether operation is by single-phase (e.g. 220/240V~, 50Hz, 1ph) or three-phase (e.g. 380/415V~, 50Hz, 3ph) supply. It will also provide:

a)

kW/hp of motor which is needed to select a starter of the correct rating. Modern motors are rated in kW (kilowatts) which indicates the output power of the motor. The switching capacity of the starter must not be less than this figure. Published data for the starter will list its kW rating against the duty category AC-3. Older motors may be rated in hp only, in which case the power in kW = hp x 0.746.

b)

Full load current (f.l.c.) which you also need to ensure that the starter selected is fitted with an appropriately-rated overload device. Starters in the Eaton MEM range are more commonly found in three phase applications, but are perfectly suitable for single phase use. However, wiring these starters for single phase use requires different connections.