Pneumatic start assembly
The pneumatic starters are positive displacement, expander type motors powered by either gas or air. Ground vehicles such as trucks with diesel engines utilize a pneumatic self-starter with a geared turbine, air compressor and pressure tank. Aircraft gas turbine engines use mobile ground based pneumatic starting engines usually called as start cart or air start cart. Large diesel generators that are usually found in large shore installations make use of a pneumatic starting gear. These starters carry more acceleration torque and cranking speed characteristics needed to start industrial type gas engines. Typically, the starter is equipped with a clutch option with positive engagement on demand.
Electric start assembly
Electric start assembly is a complete system with pre-programmed motor controller, variable speed AC motor and an overrunning clutch. The use of electric starters is strongly recommended in place of gas expansion turbine starters that emit methane. The six common types of electric starters are full voltage, reduced voltage, part winding, Wye-Delta, primary resistance and soft starters.
Full voltage starters are the most commonly used electric starters because of the placement of the motor across full voltage supply lines. Various types of full voltage starters include magnetic, reducing or reversing and a combination of both. Reduced voltage starter is important for pumping motors as it enables the motor to adjust to pressure before accelerating fully. Primary resistance starter is usually used in motors that are running conveyors belts carrying fragile items. It works by distributing power to the motor through resistors. Wye-Delta starter starts a motor with reduced current and lowest starting torque and typically used for motors that are running appliances and lights.
Hydraulic start assembly
Hydraulic start assembly are Hilliard starters that feature a variable speed hydraulic piston motor and overrunning clutch ready for on-engine installation. Although the electrical and pneumatic starters are standard for many types of equipment, the hydraulic starter has found its niche in remote and potentially hazardous locations such as marine, oil and gas, power generation and mining industries. The hydraulic starter typically works as the primary or auxiliary emergency starting system. The major advantage of the hydraulic starter is it cranks engines. It is faster at a higher torque so that the engines can start more quickly. The instant availability of torque is significantly beneficial in cold weather. In addition, the absence of electrical connections results into a spark-proof starter operation.