Synchronous Motors: Overview

 

  Synchronous Motors

Power supply AC  
Driver electronics need No  
Speed accuracy High Not effected by load torque 
No closed loop speed control need
Speed control No Not possible
Speed fixed by mains supply frequency
Position control No Not possible
Only by limit switches
Overloadablity / load inertia Low Only little reserve for peak load torque
Can’t accelerate high inertia
Lifetime High Limited by bearings
Depends on lateral force
Speed range [rpm] 250…3600 Depend on pole number and mains frequency
Efficiency 15…45%  
Power vs. size Low
Winding thermal protection No need Inductance protected
(if winding designed for 100% duty cycle)
Load sensing Difficult Load has little impact on current
Stalling permissible Yes If winding designed for continuous duty cycle
Electromag.interference EMI Not Critical No brushes
Braking/Holding torque Low Detent torque (when power switched off)
Linear motors from JE Yes
JE brand Saia Johnson Motor