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- PHY102 Physics II © Dr.Cem Özdoğan
- 28-9 Torque on a Current Loop
- The elements of an electric motor
- The elements of an electric motor:
- A rectangular loop of wire, carrying a current and free to rotate about a fixed axis, is placed in a magnetic field.
- Magnetic forces on the wire produce a torque that rotates it.
- The two magnetic forces F and –F produce a torque on the loop, tending to rotate it about its central axis.
- A commutator (not shown) reverses the direction of the current every half-revolution so that the torque always acts in the same direction (FYI).
- Magnitude of the total torque on the coil (of area A and N turns):
FB=ibBsinφ , φ=90
τ=rFB=aibBsinθ
τ=(iA)B=μB
μ:magnetic moment