AMETEK Dynamic Fluid Solutions manufactures a wide range of bypass motors for vacuum and blower applications. In bypass motors, the working air is independent from the cooling air. A separate fan is used to direct cooling air over the armature and field.
Manufacturers should ensure that the cooling air does not mix with the vacuum or blower air. Cooling air is typically made available through an egress in the equipment housing.
Bypass motors come in two configurations: Peripheral Bypass and Tangential Bypass. The method a manufacturer chooses depends on the method of mounting and air ducting geometry because the working air does not travel across the motor at all. This style of motor is a dependable choice for wet pickup applications such as scrubbers and carpet extraction.
Bypass motors are available in single or multiple stages. The stages are used to create more pressure if used as a blower or more life if used as a vacuum. Single stage motors typically have the highest air flow/air watts while the lowest vacuum levels.
Adding fan stages increases the vacuum capability of the unit but reduces the air flow. This is because of increased impedance to air flow through the system, the result of additional fans (rotating and stationary) through which the air must pass.