The 31813 series low speed synchronous motor is a development of the standard industrial series specifically designed for use in high quality record decks that utilise the belt drive principle. Particular attention has been given to the magnetisation of the 24 pole rotor to optimise smooth running. This, together with the high accuracy of stator pole placement minimises torque ripple and provides low audible noise. The motor which is designed for mounting horizontally with output shaft vertically up is provided with an increased shaft length and a 3 mm diameter to aid the fitting of the drive pulley. When fitting the drive pulley the shaft rear end should be supported to ensure that the axial load limitation is not exceeded. The windings have been specifically designed to facilitate dual voltage operation, a 6.8K Ohm resistor being used in series when operation from a 220 Vac supply is required. Dimensions mm. Specification Nominal Voltage Vac 110 Max Working temperature deg. C 105 Permissible voltage fluctuation % -15 / +10 Ambient temperature range deg. C -5 to +70 Supply Frequency Hz 50 Torque derating % / OC 0.25 Speed @ 50 Hz rpm 250 Insulation according to CEE10 Class 2 Direction of rotation reversible Insulation test voltage V 2500 Direction control capacitor µ F 0.22 ( 250 Vac ) Maximum radial force N 5 Input Power W 1.8 Maximum axial force N 1.5 Input current mA 18 Mass g 16 Housing zinc plated Bearings slide Connections Mclenn
The 31813 series low‑speed synchronous motor is designed for high‑quality record decks that use a belt‑drive system. It features a 24‑pole rotor with optimized magnetisation for smooth running and low audible noise. The motor is intended for horizontal mounting with the output shaft pointing vertically upward, and includes an extended 3 mm diameter shaft for easy pulley attachment.
The guide provides detailed mechanical and electrical installation instructions, recommended anti‑vibration mounting methods, and guidance on dual‑voltage operation using a 6.8 kΩ series resistor and a 0.22 µF direction‑control capacitor. Adjustments such as trimmer resistors and capacitors are described to fine‑tune performance and minimise torque ripple.
| Nominal Voltage | 110 Vac |
|---|---|
| Maximum Working Temperature | 105 °C |
| Ambient Temperature Range | -5 °C to +70 °C |
| Supply Frequency | 50 Hz |
| Speed @ 50 Hz | 250 rpm |
| Input Power | 1.8 W |
| Input Current | 18 mA |
| Mass | 16 g |
| Direction of Rotation | Reversible |
| Direction‑control Capacitor | 0.22 µF (250 Vac) |
| Dual‑Voltage Resistor | 6.8 kΩ series resistor |
The motor is rated for a nominal voltage of 110 Vac.
It should be mounted horizontally with the output shaft pointing vertically upward, using an anti‑vibration pad and rear shaft support.
A 6.8 kΩ resistor is placed in series when the motor is run from a 220 Vac supply.
A 0.22 µF direction‑control capacitor is specified for 250 Vac operation.