Power packs are easy to operate as they are ready assembled and easy to control. The use of power packs is always recommended when jobs have to be done in a time-saving and efficient way, when repeating jobs have to be finished off, quick cylinder cycles have to be achieved or if large oil volumes in connection with high tonnage cylinders have to be transmitted.

Two-stage output
The standard Yale power packs are equipped with two-stage pumps, which means that a low pressure stage fills the connected hydraulic cylinder quickly
up to a pressure of 80 bar. The high pressure stage is activated automatically from 80 bar up to 700 bar, while the low pressure stage is discharged back to the reservoir. This economic solution avoids heating-up, saves energy and keeps the power packs compact.

Single-stage output model PYE
The hydraulic packs have single-stage pumps. These packs deliver between 0 and 700 bar with the same volume (high-pressure stage).

Control/Operation
The motion control of the connected hydraulic cylinder is done by operating the directional valve.

Do you have a single-acting or a double-acting hydraulic cylinder?
The directional control valve has to correspond to the a.m. functional principle of the hydraulic cylinder to be operated. Depending on these principles the power packs are equipped with a:
      3/3-way valve to operate single-acting hydraulic cylinders (connection with one hydraulic hose)
      4/3-way valve to operate double-acting hydraulic cylinders (connection with two hydraulic hoses)
The directional control valves are available either as manual or solenoid operated valves.

Operation of the directional valves
Depending on the way of operation, there are manual or solenoid operated valves. Manual valves are controlled by shifting the operating lever and represent the economic way of control.
These valves have 3 lever positions:
- advance - hold - retract -

Solenoid valves
Solenoid valves have the advantage that they are controlled by a pendant remote control box which makes the operator independent from the power pack, making it easier for him to monitor the job. The solenoid valves are controlled by two push
buttons - advance - hold - retract -
In neutral position - hold - the valves rest in pressureless circuit. Pressure and force of the connected cylinder are held without pressure drop. The complete
electrical set-up (with 24 V control) belongs to the scope of delivery. Solenoid valves allow a very ergonomic operation and offer a quick and precise switching (millimeterwise) of the connected hydraulic cylinder.
Pressure-less circuit
In neutral position all directional valves rest in pressureless circuit which means that the oil flow coming from the rotating pump is guided back to the reservoir without creating any pressure build-up.
Special solenoid valve configurations
Some applications require a special valve configuration, e.g. the independent control of several hydraulic cylinders from a single power pack. In such cases the complete valve build-up and electrical control is made
to the customer‘s requirements.
Pressure-Guard power packs
By using an electro-hydraulic pressure switch and a special electric control, power packs can selfcontrol their pre-adjusted pressure. In applications where the pressure (load) should be applied over a very long period, the connected power pack is switched on and off automatically and replaces the pre-set pressure in case a pressure drop has occured.
Trolleys
For all power packs we offer a cart-frame for flexible movement from job to job. Cart-frames are equipped with 2 fixed and 2 swivel castors.
Oil cooler
For certain applications, especially when power packs are continuously operated and the oil temperature could exceed 60? C, the use of an oil cooler is recommended.
Hydraulic oil
All power packs are designed to be operated with standard hydraulic oil (specification ISO VG 32). For certain operating conditions the viscosity class of the hydraulic fluid can be varied. All power packs are supplied including oil.

Features
- Robust packs, also capable for contiuous applications.
- Suitable for all jobs in workshops and on construction sites where hydraulic force is required;supplied ready to use.
- On-off motor switch and 3 m motor connecting cable.
- With carrying handles, oil level gauge, oil filler/resevoir ventilation plug.
- Incl. pressure gauge GGY-631.
- Two-stage displacement, which means a rapid advance without load, as well as an automatic switch into the 2. phase by a congruous load.
- Low noise level due to standard motors with 1450 rpm.
- Futher motor voltage and oil resevoirs on request.
- With manual or solenoid operated directional valves.
- Solenoid valves with 3 m remote control box (with 2 push-buttons) and pressure set valve as standard. Adjustable from 0-700 bar.
- 24 V - low voltage control includes a sturdy metal electric control box and ready to use set up.