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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.

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

1 Answer 1

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Unless the number of magnets is changed, the base speed can be changed only by changing the base frequency and base voltage. That would not change the available torque or the flux of the permanent magnets. The operating torque is determined by the load.

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  • \$\begingroup\$ Thanks a lot for your answer. What would happen to the permanent magnet flux if the base speed would be doubled? \$\endgroup\$
    – Nytro
    Jan 18, 2022 at 20:10
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    \$\begingroup\$ Ii would not change (added to answer). \$\endgroup\$
    – user80875
    Jan 18, 2022 at 21:02

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