• 15 parts
  • Checked September 2026

Parts of a Blower Motor

A furnace blower assembly from the motor side, then the motor and wheel pulled out.

Parts of a Blower Motor

Name Date

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
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Write the name of each numbered part.Answer key

  1. Blower motor
  2. Blower wheel
  3. Blower housing
  4. Air inlet
  5. Outlet
  6. Cutoff plate
  7. Mount arms
  8. Capacitor
  9. Capacitor strap
  10. Motor leads
  11. Mounting band
  12. Motor shaft
  13. Hub
  14. Setscrew
  15. Blades

Drawn for this site on 2026-09-30 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: the furnace it sits in

All 15 parts on the diagram

Show the list

Housing and air path 4

  1. Blower housing It gathers the air flung off the wheel. It directs that air to the outlet.
  2. Air inlet Air enters here, from the side, into the middle of the wheel.
  3. Outlet The air turns 90 degrees inside the housing and leaves here.
  4. Cutoff plate It sits at the outlet of the housing, close to the wheel.

Motor and mount 6

  1. Blower motor In a direct-drive blower it sits inside the wheel. It turns the wheel directly.
  2. Mount arms They hold the motor in the housing. Their ends are screwed to it.
  3. Capacitor It stays connected to the motor all the time the motor runs. It is a run capacitor.
  4. Capacitor strap It holds the capacitor to the blower housing.
  5. Motor leads They connect the motor to the capacitor and the furnace control board.
  6. Mounting band A screw tightens it round the motor. The mount arms are fixed to it.

Wheel and shaft 5

  1. Blower wheel A drum of blades mounted around a hub. It flings the air outward as it spins.
  2. Motor shaft It has a flat side where the setscrew bears.
  3. Hub The center of the blower wheel; it slides onto the motor shaft.
  4. Setscrew It fastens the wheel to the flat on the motor shaft.
  5. Blades Air speeds up as it flows over them.

How this list was compiled: Every name checked on 2026-09-30, a name kept only where two independent sources use it. Three furnace makers' manuals, read as full text on archive.org: one maker's blower-motor kit instructions and service manuals (https://archive.org/details/manualzilla-id-5788453 and https://archive.org/details/manualzilla-id-6015757; one company, counted once), a second maker's service manual (https://archive.org/details/manualzilla-id-7320716) and a third maker's furnace manual with parts lists (https://archive.org/details/manualzilla-id-7379278). Wikipedia, Centrifugal fan and Motor capacitor. No maker is named on the page. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; a schematic of no maker's blower, nothing traced. Licence: own work

How it works

A blower motor works inside a blower assembly: the motor, the wheel it turns and the housing round both. The first drawing shows a furnace blower from the motor side. The second pulls the motor and wheel out and cuts the wheel through.

Read the full guide

The whole assembly, then the motor and wheel

Numbers 1 to 10 are on the whole assembly. The blower motor sits in the middle of the blower wheel, held to the blower housing by the mount arms. Air comes in through the air inlet at the side and leaves by the outlet on top, past the cutoff plate. The capacitor is held by its strap, and the motor leads run to it. Numbers 11 to 15 are in the side view. The mounting band clamps round the motor. The motor shaft runs into the hub of the wheel, where the setscrew fastens it, and the blades run the length of the wheel.

  • This blower is direct drive: the wheel sits on the motor's own shaft. A belt-drive blower has a belt and pulleys between the two.
  • Blower wheel, fan wheel and squirrel cage are names for the same part.

Questions and answers

What are the parts of a blower motor called?

The blower motor with its shaft, leads and capacitor; the mounting band and mount arms that hold it; the blower wheel with its hub, setscrew and blades; and the blower housing with its air inlet, outlet and cutoff plate.

What is the squirrel cage on a blower motor?

The blower wheel. It is a drum made of many blades mounted around a hub. Air enters the wheel from the side, speeds up as it flows over the blades and leaves through the housing.

What does the capacitor on a blower motor do?

It is a run capacitor wired to the motor by its own leads. A permanent-split capacitor (PSC) motor keeps its capacitor connected all the time it runs.

What holds the blower wheel on the motor?

A setscrew in the hub of the wheel. It tightens against the flat side of the motor shaft.

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