Design and variants
- an SKF Explorer deep groove ball bearing in the 62 series with a snap ring groove in the outer ring (→ Single row deep groove ball bearings) and an RS1 contact seal
- an impulse ring
- a sensor body
cable outlet and connecting cable
The signals can be interpreted by motor controllers in different ways:
- The direction of rotation can be determined from the phase shift, when the rising edge of a signal first appears.
- Slow speeds can be determined by measuring the time between two electrical events, events being the rising and falling edge on either square wave.
- High speeds can be measured by counting the number of electrical events within a given time period.
The two square waves are 90° out of phase with each other. This phase shift changes sign with the direction of rotation. Fig. 2 shows the general specifications of the signal. The presence of two signals in quadrature enables a processing unit to multiply the number of angular position increments per revolution. For example, using a standard SKF sensor bearing with 64 pulses per revolution and a standard electronic interface that can detect the rising (Low/High) and falling (High/Low) times of each of the two signals, it is possible to obtain 256 electrical events per revolution, which translates to an angular resolution of 1,4° (fig. 2).
SKF motor encoder units provide accurate and reliable signals for effective motor control and are 100% tested for period accuracy, duty cycle and phase shift during manufacture.
For alternative connectors or cable lengths, contact the SKF application engineering service.
Motor encoder units are considered relubrication- free. The grease life in the bearing can be calculated according to the method described under Grease life for capped bearings.
For additional information about motor encoder units for extreme operating conditions, contact the SKF application engineering service.