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January 19, 2024

Synchronous Power Units - A Game Changer

Hydra-Slide's Synchronous Power Units enable you to raise and lower a load synchronously, maintaining level at all times.

Our Synchronous Power Units (SPUs) provide equal flow to each port, regardless of the weight distribution of the load. This means that raising and lowering a load can be done simply by operating a single master control valve- no need for end-to-end jacking, no need to worry about the load's precise centre of gravity.

Read on to learn how SPUs work, and how they can be a real game-changer for many jacking and skidding projects.

SPU Benefits - Besides Faster Skidding

Some loads- like the fully dressed 650-ton transformer shown on the right- need to remain level, otherwise there is a risk of damage.

Loads like this can certainly be jacked and lowered using a conventional power unit, however in that case the rigging crew needs to be especially careful to maintain level- e.g. by jacking very slowly end-to-end, or by feathering valves on the power unit to equalize the flow rates manually. 

In contrast, SPUs provide equal flow rate to each hydraulic line regardless of pressure. That means that the load will remain level during jacking and lowering, even if the weight is not evenly distributed across all lifting points. Since the pump itself takes care of maintaining equal flow rates, the job can typically be accomplished more quickly and more safely. 

For a really deep dive into the operation and maintenance of these synchronous units, click below to watch our full training video (25 min):


Watch Training Video



How Do SPUs Work?

Conventional lifting circuits divide the hydraulic oil flow from the pump into multiple outlets. Since the outlets are all connected to one another, the result is that each outlet will exhibit equal pressure, but not necessarily equal flow. That hydraulic pressure translates into lifting force at the piston of each hydraulic cylinder, and this force is what lifts the load. So for example, when lifting a load which is not equally distributed across all lifting points, the force of gravity acting on each point is not equal: the jacks with greater weight on them will tend to extend more slowly, and jacks with less weight will tend to extend more quickly. If it’s critical that the load remains level at all times, this is a problem.

At the heart of every synchronous power unit is a split-flow hydraulic pump. Unlike conventional hydraulic pumps, a split-flow pump uses its main shaft to drive a number of pistons- one piston for each pressure port. Essentially, each piston in the pump acts like its own miniature pumping unit. Since each circuit is independent, and each piston stroke displaces the same volume, the flow rate coming from each port is equal, and does not vary with changes to the pressure in the line.

Hydra-Pac power units enable you to synchronize your cylinders, and then simply raise and lower all points simultaneously using a single master control valve- no need worry about the load’s precise centre of gravity, or the hydraulic pressure at each cylinder. If the load is unbalanced, you may see different pressure readings on the individual jacking cylinder ports, but this would only become an issue if any of the circuits exceed the maximum pressure rating of the system.

One additional benefit of the Hydra-Pac SPU’s design is that ports can be paired together to substantially increase skidding speeds. We have often heard riggers complain that hydraulic skidding can be a slow process, especially with smaller, conventional power units that have comparatively low hydraulic flow rates.

To address this concern, we’ve added extra valves (one for each pair of ports) that can be opened to effectively double skidding speed by combining the oil output of each pair of circuits into a single port. Of course, this means the number of available ports is also halved.

The Hydra-Pac Synchronous pump, 59-8-8D (PU) - courtesy of Bonneville Power.JPG

Hydra-Pac Synchronous


  • Multiple independent oil circuits
  • Equal flow regardless of weight distribution
  • Safely lift, lower and slide any load on all points simultaneously
  • Maintains uniform pushing/pulling forces
  • Ports can be combined for faster skidding
  • Available with electric, diesel, or propane drive 
  • Available with four, six, or eight ports



  • Single oil supply circuit
  • Compact and portable
  • Lower cost
  • Often require end-to-end jacking operations
  • Available with electric or gasoline drive
  • Available with two or four ports
  • Ideal as a backup unit



A Synchronous Power Unit can help to make skidding, jacking, and lowering operations safer, faster, and easier. Click below to find details and specifications on our Hydra-Pac line of power units, or contact us directly - we're always happy to help you choose the best equipment for your needs.


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