I have a strange problem with instaspin based 230VAC drive implementation. The drive works well, however, the actual motor speed seen with gMotorVars.Speed_krpm variable inside the drive matches with actual drive speed upto 2000rpm, after this, the actual motor speed and speed shown in above variable differs.
For example,
With 10pole motor, upto 2000 rpm, the actual motor speed and gMotorVars.Speed_krpm is identical, however, beyond 2200 rpm, the actual motor speed(3600rpm) is much higher than gMotorVars.Speed_krpm(2500rpm)
With 8 pole motor, the same phenomenon is seen the actual speed and the gMotorVars.Speed_krpm speed are identical upto 2000 rpm, but later the variation is seen in these values and the actual motor speed is 3600rpm when gMotorVars.Speed_krpm shows 3000rpm.
The variation increases linearly.
The motor performance, current values are all OK -the only problem is difference between actual speed and gMotorVars.Speed_krpm.
I have doubly checked motor pole pair and they are correct in both above cases.
Can somebody pl. help me and throw some light on this? How does the instaspin library calculate the speed in gMotorVars.Speed_krpm?
