The Ametek Lamb 116757 is a two-stage, 5.7-inch quiet-bypass motor with peripheral discharge, wired for 120 volts. The quiet-bypass build is what gets it specified where noise is a real constraint, in car wash vacuum stations, in central vacuum power units mounted near living or working space, and in commercial machines run during occupied hours. At 7.9 amps it is also one of the gentler motors on a circuit in its class, which matters when several stations share a panel.
Built for
- Self-serve car wash vacuum stations where noise and circuit load both matter
- Central vacuum power units mounted near occupied space
- Commercial canister vacuums run during business hours
- Wet and dry recovery machines built around a peripheral-discharge bypass motor
- Replacement stock for 5.7-inch two-stage quiet bypass motors
How this motor works
A bypass motor carries a separate cooling fan, so the air that cools the armature and field never mixes with the air being pulled through the machine. That separation is the whole reason bypass motors are specified for wet recovery work such as carpet extraction and autoscrubber recovery, where the airstream is carrying water, foam and cleaning solution. It also means the motor is not being cooled by whatever the operator happens to be picking up.
Peripheral discharge exhausts cooling air around the full circumference of the motor housing rather than through a single port. In a canister or power unit that has room around the motor, peripheral discharge keeps exhaust noise diffuse and simplifies the mounting, which is why it shows up so often in central vacuum power units and quiet-bypass builds.
The quiet-bypass designation, abbreviated QBP, is about how the motor manages its own exhaust rather than any change to the airflow principle. Combined with peripheral discharge, which spreads exhaust around the housing instead of firing it out one port, it is a noticeably less fatiguing motor to stand next to through a shift.
Carbon brushes are the wear part on any Ametek Lamb motor, not the motor itself. Ametek's own guidance is that a set of brushes can be changed twice before the armature and the rest of the assembly need replacing, with roughly 60 percent of original life left after the first change and about 40 percent after the second. If a machine has begun surging, losing suction intermittently, or throwing sparks at the commutator, brushes are the first thing to check before condemning the motor.
The one symptom that is not a brush job is a burning smell. Technicians on carpet-cleaning and contractor forums are consistent about this: a scorched odor means the armature has overheated where the brushes ride, and the machine should be shut down at once rather than run to the end of the job. A motor that has cooked its armature is a replacement, not a repair.
The other killer is water. Extractor and wet-recovery operators point out that it is effectively impossible to never overfill a recovery tank, and that the solution being picked up often carries degreaser. Water and foam that reach the windings do damage that no brush change undoes, which is why float shut-offs and inline filters matter as much as the motor spec does.
Ametek Lamb part numbers are not interchangeable by diameter alone. Before ordering, pull the old motor and match four things: frame diameter, number of fan stages, discharge configuration and nameplate voltage. Two motors that share a body size can have completely different gasket surfaces, lead lengths and airflow paths, and a mismatch usually shows up as a motor that physically drops in but never reaches its rated suction.
Specifications
- Fan diameter: 5.7 in
- Stages: 2
- Airflow system: bypass, quiet bypass (QBP) build
- Air discharge: peripheral
- Voltage: 120 V
- Amperage: 7.9 A
- Power: 918 W
- Maximum air watts: 255
- Sealed vacuum (water lift): 85 in
- Maximum airflow: 97 CFM
- Bearings: ball bearing, sealed against dust and dirt ingress
Fitment
Ametek publishes this base number in more than one suffix variant, including -00 and -13, and distributor cross-references generally belong to a specific suffix. No manufacturer machine compatibility list is published for the base number, and none is claimed here. Read the complete part number off your motor label and match frame diameter, stage count, discharge style and voltage before ordering.
Frequently asked questions
What does QBP mean on this motor?
Quiet bypass. It describes how the motor handles its own exhaust noise. The airflow principle is still bypass, with cooling air kept separate from the working air.
Why peripheral discharge instead of tangential?
Peripheral discharge exhausts around the circumference of the housing rather than through a single side port. It keeps exhaust noise diffuse and suits housings with clearance around the motor.
How much current does it draw?
7.9 amps at 120 volts, roughly 918 watts. That is modest for a two-stage 5.7-inch motor, which helps where several machines share one circuit.
What are the sealed bearings for?
They keep dust and dirt out of the bearing races, which is the failure path in dusty service such as car wash and construction cleanup.
Will the -13 version work in place of the -00?
Not automatically. Suffix variants differ in lead length, sealing and mounting detail. Match the complete number from your existing motor.
Discount Cleaning Products is a United States based dealer for Ametek Lamb vacuum motors and stocks the matching carbon brush kits, gaskets and mounting hardware alongside them. Our team works with these motors every day across central vacuum systems, extractors, autoscrubbers and shop equipment, and can help you confirm frame size, stage count, discharge style and voltage against the motor already in your machine before you order.
