Product overview

The 7.2 inch three-stage Lamb is the large-frame tangential bypass motor used in high-performance portables and truckmount vacuum boxes. It is the biggest of the Ametek motors CCW stocks, and it is specified where sealed lift matters more than anything else.

Specifications

Ametek model	116136-00
CCW code	AV18
Frame size	7.2 inch / 183 mm
Stages	Three
Voltage	240 V AC, 50/60 Hz
Discharge	Tangential bypass
Bearings	Double ball, 10 mm shaft and bearing system
Speed	Single speed
Fan end bracket	Aluminium
Top bracket	Aluminium
Maximum watts	1630 W
Minimum sealed vacuum	118.0 inches of water
Approvals	UL recognised, category PRGY2 (E47185)

Typical performance

Measured at 240 volts, 60 Hz, corrected to 29.92 inHg and 68 °F. Figures are from Ametek product bulletin 116136-00, revised January 2018, and represent a typical motor sampled from production. Individual motors vary.

Orifice	Vacuum	Airflow	Air watts	Amps
2.000 in	3.3 in H2O	97.3 CFM	38	6.9
1.500 in	9.5 in H2O	92.6 CFM	103	6.9
1.000 in	33.2 in H2O	77.0 CFM	301	6.9
0.750 in	59.4 in H2O	57.9 CFM	404 (peak)	6.8
0.500 in	88.7 in H2O	31.4 CFM	327	6.1
Sealed	129.0 in H2O	0 CFM	0	4.7

How to read this. Peak air watts occur at a 0.750 inch orifice, not wide open and not sealed. That is the restriction a well-matched wand and hose present, and it is why matching the tool to the motor matters more than chasing the highest sealed-vacuum figure on a spec sheet.

Design features

Patented air seal bearing construction, US Patent 4,088,424
Epoxy painted fan case
Provision for grounding

Fits

US Products HHP
Hydro-Force FX
Prochem
Century

Important. The 7.2 inch frame is physically much larger than the 5.7 and 6.6 inch motors. It is not a drop-in upgrade for a smaller housing, and the current draw is higher. Confirm the housing, the mounting and the circuit before ordering.

Manufacturer warning

Ametek's product bulletin carries an explicit warning worth repeating. Where a bypass motor is used in a machine that comes into contact with foam, liquid including water, or other foreign substances, the machine must be designed and constructed to prevent those substances reaching the fan system, motor housing and electrical components.

Lamb Electric vacuum motors other than hazardous duty models should not be used in machines that come into contact with dry chemicals or other volatile materials. Failure to observe this can cause flashing or electrical shock, with risk of property damage and severe injury.

Choosing and fitting a replacement vacuum motor

Match the frame size, stage count, discharge type and voltage. All four have to agree. A motor of the right diameter with the wrong number of stages will fit the housing and then underperform, and a peripheral-discharge motor will not seal correctly in a housing built for tangential discharge.

Stages set vacuum, not airflow. Adding a stage raises sealed lift and does comparatively little for open airflow. A three-stage motor is the choice for wands and deep extraction where the tool restricts flow; a two-stage suits higher-flow work and draws less current.

Bypass motors need clean, dry, filtered air. The cooling air path is separate from the working air path, which is exactly why these motors last — but it also means the working side must never see water or fine dust. Most motors that fail early were drowned, not worn out.

Check the brushes before you condemn the motor. Carbon brushes are the usual wear item and are far cheaper than a motor. A motor that has lost power, sparks heavily at the commutator or runs rough is often a brush job.

Replace the gasket and check the mount. A vacuum motor is only as good as its seal. Refitting a new motor onto a hardened gasket leaks air and costs lift. Inspect the mounting spring or grommets at the same time — vibration transmitted into the housing shortens motor life.

Documents

Ametek product bulletin 116136-00, revised January 2018 (PDF)

The performance table above is taken directly from this bulletin.