Accumulators Give Your Winch a Boost

We frequently get questions about the function of the accumulators inside every Allied powershift towing winch. They may seem like just an optional part of the system if you are never aware of the service they provide. But, in fact, they are quite important.

The accumulators serve two key purposes:

1. To supply additional hydraulic oil when the PTO shaft is turning slowly and unable to deliver its normal capacity of oil. The additional oil ensures that the brake and clutch function just like they would when the PTO is turning at normal speed.
   
   

2. To allow the operator to maintain hydraulic function if the tractor engine shuts off, usually to release the brake and unhook the load.

In simple terms, the accumulator is a steel chamber divided into two parts by a rubber diaphragm, with nitrogen gas contained in one part and hydraulic oil in the other part. The nitrogen side of the accumulator is sealed and normally remains filled with nitrogen gas to a pressure of 115 psi. The other side of the accumulator is connected to the winch hydraulic system, and responds to the changing pressures in the system.

If the system side of the accumulator is at 225 psi, then the nitrogen gas is compressed until its pressure reaches 225 psi. The accumulator becomes filled mostly with hydraulic oil, and is available for use if the system pressure drops.

The two events that cause a normal drop in system pressure are a slow turning PTO, usually due to a heavy load, or a PTO not turning because the engine shuts off.

It may be tempting to charge the accumulator with compressed air. This practice is not recommended. Air reacts chemically with the rubber, causing breakdown of the rubber diaphragm and failure of the accumulator. In addition, the air may be saturated with water or other contaminants, which can also damage the rubber diaphragm.

Until recently, all winches contained two accumulators. Allied now uses a single larger accumulator in the W6F and W8L winches. If you would like to convert an existing winch to the new style accumulator, Allied offers a conversion kit, Part Number 2304704W.

Help your customers by keeping the accumulators charged and in working order.