|Electrical Machines - Basic vocational knowledge (Institut für Berufliche Entwicklung, 144 p.)|
|7. Single-phase alternating current motors|
|7.4. Single-phase commutator motors (universal motors)|
A universal motor can be driven both by single-phase and direct current voltage. Both assembly and circuitry correspond to direct current series motors.
Figure 120 - Circuitry of a universal motor with interference suppression capacitor
1 Direct current
2 Alternating current
3 Terminal designations
Because of the low power and subsequent minimal incidence of commutator sparking, universal motor stators dispense with interpole and compensation windings.
Figure 121 shows the lamella section of a universal motor. The exciter windings, also known as pole or field coils, have been positioned on the pole core.
Figure 121 - Lamella form of a universal motor