# What happens to the permanent magnet flux of this synchronous motor?

Considering a synchronous motor with permanent magnets (1 pair)

If there is a synchronous motor with permanent magnets and I was given the initial permanent magnet flux

Y_mp = e0(at 15 rps) / w (at 15 rps) = 168.3 V / 94.2 rad/s = 1.79 Wb Y_mp = 1.79 Wb

Then I found out the base speed of the motor, w = 85.9 rad/s, and then I find out the current iq as 28.3 A and the torque = 3/2p * iq * Y_mp = 3/2128.3A1.79 Wb = 75.9855 Nm so the Torque = 75.9855 Nm

Now, what happens if the base speed is doubled? Such as having w = 171.8 rad/s, what would happen to the permanent magnet flux? Will it change? If so, is there a way to calculate the new permanent magnet flux? I need that in order to calculate the new torque after the base speed was doubled.

• Exactly what do you mean by doubling the base speed? Jan 18, 2022 at 21:00
• @user28910 the calculated base speed at which the rotor is spinning, so doubling it basically. Jan 18, 2022 at 21:03