The Ametek Lamb 117478 is a two-stage 7.2-inch bypass vacuum motor for 120-volt equipment and one of the stronger motors in the 7.2-inch Premier family. At a peak of 549 air watts it sits well above the 5.7-inch two-stage motors, which is why it shows up in central vacuum power units and in commercial machines that need lift and airflow together rather than one at the expense of the other. Bypass construction keeps cooling air out of the working airstream, so it suits wet pickup as well as dry.
Use cases
- Re-motoring a central vacuum power unit that has lost suction at the far end of the house.
- Replacing the vacuum motor in a 120-volt commercial canister or wet/dry extraction machine.
- Building or repairing material-handling and transfer equipment that needs high air watts on a standard 120-volt circuit.
- Upgrading from a 5.7-inch two-stage motor where the housing has room for a 7.2-inch frame.
Specifications
- Ametek Lamb part number 117478, catalogued by Ametek as 117478-12
- Two stage
- 7.2-inch (183 mm) diameter
- 120 volts, 50/60 Hz, single speed
- Tangential bypass discharge
- Double ball bearings
- Maximum sealed vacuum 120.0 inches of water
- Maximum airflow 115.8 CFM
- Peak output 549 air watts
- 1115 to 1595 watts across the published performance curve
- Aluminum fan-end and commutator brackets
- 10 mm shaft and bearing system
- Epoxy-painted fan case
- Three-bolt mounting; the motor gasket is a separate part
- UL and CSA recognized
- Carbon brush kit 833450-57
Choosing and fitting
Published compatibility for this motor is stated at the brand level rather than by unit model, and the available sources disagree with one another, so we do not publish a fitment list. Confirm the part number, diameter, bracket style, bolt pattern and overall height against your existing motor before ordering. Published amperage figures also differ between the Ametek performance curve and distributor listings, so we do not quote an amp rating. The casting on an older unit may be marked 7478 or 11-7478 rather than the full number. Replace the mounting gasket whenever a motor is changed.
Frequently asked questions
Is 117478 the same motor as 117478-12?
Yes. Ametek catalogues this motor as 117478-12; the shorter 117478 is the number most distributors and machine builders use. Order either and you receive the same two-stage 7.2-inch 120-volt motor.
Can this motor be used for wet pickup?
Bypass motors are the type used in wet/dry machines because cooling air never passes through the recovered airstream. That said, wet capability belongs to the machine as a whole, including its float shutoff and recovery tank. Follow your equipment maker's guidance rather than the motor specification alone.
Two-stage or three-stage: which should I order?
Service technicians generally judge a motor by where airflow and water lift cross on its performance curve and by what it draws to get there, not by stage count. A strong two-stage motor such as this one can out-perform a smaller three-stage motor on open-hose airflow, while three-stage motors hold up better under heavy restriction. Match whatever the machine was designed around.
What brushes does it take?
Carbon brush kit 833450-57. Replacing brushes before they wear to the limit protects the commutator and is far cheaper than a second motor.
Discount Cleaning Products is an authorized dealer for Ametek Lamb vacuum motors and stocks the brushes, gaskets and service parts that go with them. Our US-based team can help you match a replacement motor to the machine you already own.
