The Ametek Lamb 116474 is a two-stage, 5.7-inch bypass motor with tangential discharge and double ball bearings, wired for 120 volts. It appears in Ametek's own Lamb Electric motor guide under the code 5.7BPT and uses a non-clog fan. Buyers are typically rebuilding a wet and dry recovery machine, a portable extractor or a central vacuum power unit whose housing was designed around a side-discharge motor, and they want the machine back at its original suction rather than close to it.
Built for
- Rebuilding a wet and dry recovery machine or portable extractor
- Central vacuum power units with a side-discharge motor housing
- Commercial canister vacuums on 120-volt service
- Service benches keeping a 5.7-inch two-stage bypass spare on the shelf
- Blower and air-mover duty on clean, dry, filtered air
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.
Tangential discharge routes cooling air out through a single side port, which lets the machine builder aim the exhaust deliberately, into a muffler, a sound baffle, or straight out of the cabinet. On extractors and compact commercial machines where the motor sits in a tight enclosure, that directed exhaust is often the difference between a motor that runs cool and one that heat-soaks.
The non-clog fan matters more than it sounds. On recovery work the airstream carries lint, fiber and debris, and a fan geometry that sheds that material is what keeps a motor at its rated airflow through a season rather than slowly choking down.
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.
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
- Air discharge: tangential
- Voltage: 120 V
- Input power: 1,250 W
- Maximum amps: 9.9 A
- Maximum air watts: 301
- Sealed vacuum (water lift): 93 in, per the Ametek Lamb motor guide
- Maximum airflow: 97 CFM
- Speed: 19,367 RPM
- Bearings: double ball bearing
- Overall height: 6.9 in
- Fan: non-clog
- Ametek guide code: 5.7BPT
- Replacement brushes: MTR503
Fitment
Neither Ametek nor any distributor publishes a machine compatibility list for 116474-00, so none is claimed here. Circulating claims that this motor is interchangeable with certain other Ametek part numbers could not be confirmed against a documented source and are not repeated. Compare overall height, bolt pattern and discharge orientation against the motor you are removing before ordering.
Frequently asked questions
What replacement brushes does 116474 take?
The published brush part number for this motor is MTR503. Brushes are the normal wear item and can generally be changed twice before the motor itself is due for replacement.
What does the 5.7BPT code in Ametek's guide mean?
It is Ametek's shorthand for the family: a 5.7-inch frame, bypass airflow, tangential discharge. It identifies the configuration, not the individual part number.
How tall is this motor?
Overall height is 6.9 inches. Check that against the motor you are removing, because a bypass motor of the same diameter can be noticeably taller or shorter depending on stage count.
Will it fit my machine?
There is no published machine list for this part number. Match frame diameter, stage count, discharge style, voltage, overall height and bolt pattern against the motor currently installed.
What is a non-clog fan?
It is a fan geometry designed to shed lint and fiber rather than pack it in, which helps a recovery machine hold its airflow over time.
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.
