به الگوریتم و مثال زیر توجه فرمائید.
Application : Driving of conveyor
Voltage : 100 V
Speed : 30 min–1
Working condition : Continuous
Frequency : 60 Hz
Select a motor that meet the above.
(1) Speed suitable for specifications
Because the required speed is 30 min–1, the gear ratio that realizes a rated motor speed (60 Hz area) of 1500 to 1550 min–1 is 1500/30 to 1550/30 = 50 to 51.67. Therefore use a gear ratio of 1/50.
(2) Calculation of required torque
Measure the approximate load with a spring balance etc. Assume that it is 2.65 N•m (375.27 oz-in).
After referring to our catalog, select M81X25G4L and install MXBG50B as a reduction gear.
(3) Actual measurement of minimum starting voltage, minimum stable voltage and speed
Assume that the following are obtained as a result of actual measurement.
Minimum starting voltage: 75 V
Minimum stable voltage: 55 V
Speed: 1700 min–1
(4) From speed-torque curve of 4-pole 25 W induction motor
Ts : Starting torque Ts = 0.16 N•m (22.66 oz-in)
Tm : Stalling torque Tm = 0.25 N•m (35.4 oz-in)
The torque is proportional to the square of the voltage and the following values are obtained.
(Minimum starting torque)
0.16 x (75/100 )2 = 9 x 10–2 N•m (12.75 oz-in)
(Minimum required stalling torque)
0.25 x (55/100)2 = 7 x 10–2 N•m (9.91 oz-in)
(Torque at motor speed of 1700 min–1) = 0.12 N•m (16.99 oz-in)
From the above, it can be seen that this application is a constant torque load and that the 4-pole 25 W induction motor still has a more than sufficient capacity. In addition, as is evident from the S-T curve of the attached S-T data, Ts and Tm of the 4-pole 15 W induction motor are as follows:
Ts = 0.1 N•m (14.16 oz-in)
Tm = 0.15 N•m (21.24 oz-in)
Considering the voltage drop and variation when used for conveyors, Ts and Tm of the 4-pole 15 W induction motor at 90 V are assumed to be as follows:
Ts = 0.08 N•m (11.33 oz-in)
Tm = 0.12 N•m (16.99 oz-in)
When the voltage drop and variation or load variation is thought to be insignificant, the 4-pole 15 W induction motor and gear head MX7G50B can be used. When the voltage variation or load variation is significant, the 4-pole 25 W induction motor should be used.