117478-12 is Ametek's own catalogue number for the two-stage 7.2-inch bypass vacuum motor that most distributors and machine builders simply call 117478. If you are holding a motor stamped 117478-12, or a parts list that calls for it, this is the part. It is a 120-volt motor built for central vacuum power units and commercial machines that need real airflow and real sealed lift at the same time, peaking at 549 air watts.
Use cases
- Direct replacement where a parts diagram or motor casting calls out 117478-12.
- Re-motoring a central vacuum power unit with long trunk runs and multiple inlets.
- Service work on 120-volt commercial canister and wet/dry recovery machines.
- OEM and repair builds needing a high-air-watt 7.2-inch motor on a standard 120-volt circuit.
Specifications
- Ametek Lamb 117478-12, commonly listed as 117478
- 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; gasket ordered separately
- UL and CSA recognized
- Carbon brush kit 833450-57
Choosing and fitting
Because the same motor circulates under two numbers, cross-check the casting on the motor you are removing before ordering. Older units are sometimes marked 7478 or 11-7478. Fitment for this motor is published at the brand level rather than by machine model and the sources conflict, so we do not print a compatibility list; verify diameter, bracket style, bolt pattern and overall height yourself. Fit a fresh mounting gasket with every motor change.
Frequently asked questions
What is the difference between 117478 and 117478-12?
There is none in the box. 117478-12 is the full Ametek catalogue number and 117478 is the short form used across the trade. Both describe the same two-stage 7.2-inch 120-volt bypass motor.
How much suction does it actually make?
Published figures are 120.0 inches of water sealed vacuum, 115.8 CFM of airflow and a peak of 549 air watts. Air watts combine the two and are the fairest single number for comparing motors, though what you feel at the tool also depends on hose length, filters and how clean they are.
Do I need to replace the gasket too?
Yes, plan on it. The mounting gasket seals the motor to the housing, and a hardened or torn gasket bleeds off sealed lift that the new motor is paying to produce. It is an inexpensive part to change while the machine is open.
Why is no amp rating listed?
The Ametek performance curve and various distributor listings publish different amperage figures for this motor. Rather than pick one and present it as fact, we leave it out and publish the wattage range from the manufacturer curve instead.
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.
