A modern day residential oil burner motor operates at which RPM?

• A. 3450
• B. 1725
• C. 3600
• D. 1200

Answer: (A)

When you’re looking at a residential oil burner motor on a 60 Hz electrical system, the speed is determined by how many poles the motor has and the slip that occurs under load. A two-pole induction motor has a synchronous speed of 3600 rpm, but it can’t run at that exact speed when delivering torque—the rotor lags behind the rotating magnetic field. That lag, called slip, typically reduces the running speed to around 3450 rpm for these burners. This high-speed, two-pole design provides the necessary torque for driving the blower and fuel pump efficiently.

So 3450 rpm is the typical operating speed for a modern residential oil burner motor because it reflects the practical running speed under load, not the ideal no-load speed. The other values correspond to different motor configurations or the exact synchronous speed without slip: 3600 rpm is the theoretical no-load speed, 1725 rpm would be a four-pole design, and 1200 rpm would be a much slower, low-speed motor.