YASKAWA Servo Motor SGM-01A3SU31 0.87A 0.318N.m BRAND NEW FREE 1YR WARRANTY

 
 
 
OTHER SUPERIOR PRODUCTS

SIMILAR PRODUCTS

Inside a Stepper Motor
There are several designs of stepper motors. For the time being, we’ll concentrate on the most popular variety, the four-phase unipolar stepper, like the one in Fig. 19.1. A unipolar stepper motor is really two motors sandwiched together, as shown in Fig. 19.2. Each motor is composed of two windings. Wires connect to each of the four windings of the motor pair, so there are eight wires coming from the motor. The commons from
the windings are often ganged together, which reduces the wire count to five or six
instead of eight (see Fig. 19.3).

WAVE STEP SEQUENCE
In operation, the common wires of a unipolar stepper are attached to the positive (sometimes the negative) side of the power supply. Each winding is then energized in turn by grounding it to the power supply for a short time. The motor shaft turns a fraction of a revolution each time a winding is energized. For the shaft to turn properly, the windings must be energized in sequence. For example, energize wires 1, 2, 3, and 4 in sequence and the motor turns clockwise. Reverse the sequence, and the motor turns the other way.

FOUR-STEP SEQUENCE
The wave step sequence is the basic actuation technique of unipolar stepper motors. Another, and far better, approach actuates two windings at once in an on-on/off-off fourstep sequence, as shown in Fig. 19.4. This enhanced actuation sequence increases the driving power of the motor and provides greater shaft rotation precision. There are other varieties of stepper motors, and they are actuated in different ways. One
you may encounter is bipolar. It has four wires and is pulsed by reversing the polarity of the power supply for each of the four steps. We will discuss the actuation technique for these motors later in this chapter.