Question:
We have all read at one time or another, that it is best to let your hydraulic pump run at least an hour before applying a load to the circuit. How many folks in the real world actually do this?

Choices:
Between 75% and 100%
Between 50% and 75%
Between 25% and 50%
Less than 25%

 

I for one have never read or heard of your Start-up staement Earthshaker.

Is this a Mobile thing?

Only for Cold Weather?

What was the reasoon given for such a statement?

Is this something you do with your equipment?

In my younger days I often heard a statement similar to this about a vehicle engine but that was before Multi-grade oil and all the additives to lubricants that stay where they belong and don't freeze up in the cold.

Well Bud you cought unprepared to back up my comment, I just read it the other day in one of the Whites hydraulics catalogs, but now I cant find it of course, so for the sake of discussion I will apply the my comment to mobile equipment.
I did find something on the net however.

"It's a good idea to cycle all the hydraulic functions without a load to adequately warm up the machine. Proper warm-up under no load is important to help extend the service life of the hydraulics."

http://www.gradingandexcavation.com/gec_0005_avoiding.html#2

This message has been edited. Last edited by: Ryan T,

Bud and Earthshaker,

It was standard practice at my last plant to run the systems for at least one hour prior to operation. This was done primarily for two reasons. First, since the systems did not run 24 hours a day, they had a tendency for the oil to cool down. The change in viscosity over the temperature would cause enough of an equipment operational inconsistancy that we would make defective parts on occassion. The second was mostly for the same reason, but due to the size of the systems. We had several systems with 3000 to 5000 gallon reservoirs. In order to insure the entire reservoir was turned over at least once prior to operation, standard practice was to run the pumps for approximately 30-60 minutes prior to start of manufacturing. The time really depended on outside temperature. As this was a hot forging operation, we ran the power units in a semi-heated facility. As I stated, the idea was not to extend the service life of the equipment as much as it was to maintain quality of manufacturing. However, I do believe that this procedure did increase the service life of the equipment. Hope this helps.

Marty

I have heard issues years ago here with a certain radial piston motor (can't recall brand) that would thermal shock badly if the motor was cold and the incoming oil was hot. Parts would seize due to differential expansion and destroy the motor. I think that was resolved years ago by the vendor, but it did illustrate that warmup is a good thing, including cycling the functions not just running pumps.

In reality, I think it rare for more than a few minutes in the mobile equipment that I see.

kcj

You are correct, but I would be reluctant to name a brand.

Suffice it to say that most rotary devices, especially those such as radial piston motors that have rotating valves are particularly susceptible to thermal shock. If you are lucky, you will only shear the tang between the rotary valve and the drive.

One way to help prevent this in a cold climate, short of enclosing and heating the device, is to circulate warm system oil through the case, prior to operating or turning the device, to bring the valve, internals and case up closer to operating temperature. These devices usually have multiple case connections that can be used to accommodate separate circulation through the case for warming.