HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
(OP)
I have a vendor design for driving cooling fans with hydraulic motors in series. The motors have internal case drains. Is this a problem? Could the first motor in series see a detrimental back pressure from the second motor?





RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
First motor _should_ see a backpressure of roughly half the supply pressure unless the second motor has somehow failed open.
Both case drains should go to the tank.
... Ah. Now I understand your question.
If the case and shaft seal of the first motor are not rated for full system pressure, there might be a problem. See the motor cut sheets.
Mike Halloran
Pembroke Pines, FL, USA
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
Ted
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
Any estimates? We are working with 2500 PSI system with each motor/fan at ~ 17HP.
We also have the fans controlled by proportional relief valve. Worse when max power to fans, yes?
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
Control flow, not pressure, to control fan speed.
Do you know that the motors will, in fact, demand full system pressure capacity?
I'd recommend a parallel motor arrangement with individual flow controls to control motor speed. Maybe some thermal feedback to control motor speed.
Ted
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
Although I have personally seen an application where the shaft seal contained the casing pressure up to 300 BAR. The cast iron case of the motor was the weak link, it cracked.
There are always exceptions, but to be sure, they really need to be separate.
Adrian
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
RE: HYDRAULIC MOTORS CASE DRAIN REQUIRMENT WHEN IN SERIES
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