Connecting a second hydraulic side knife

[# Robin]

Hello gents, I want to fit the second hydraulic side knife which I’ve had sat in the shed for years and I’m head scratching...

Are the two hydraulic motors normally connected in series, with the output from motor 1 feeding into motor 2?
I wondered if the back pressure would damage the 1st motor?

Or are they T’d together (maybe with a flow divider to avoid one stopping?) but it’d halve the flow?

The existing hydraulic sideknife is driven from a small dedicated pump with its own reservoir driven off the header drive. It’s a Deutz combine and the dealer’s parts book isn’t obvious.

Any photos or experience welcome!
Thanks

 

[Pheasant Surprise]

It’s a tough one to answer because it comes down to the design of the motors and specifically whether the seals are designed to handle the higher back pressure for series connection.

 

[masseybreaker]

when i did it on a nh i plumbed them in series if when cutting the hedge on the headland that one jammed the belt on the pump drive slipped so was simple and worked not saying its the right thing to do though

 

[Gapples]

Hello gents, I want to fit the second hydraulic side knife which I’ve had sat in the shed for years and I’m head scratching...

Are the two hydraulic motors normally connected in series, with the output from motor 1 feeding into motor 2?
I wondered if the back pressure would damage the 1st motor?

Or are they T’d together (maybe with a flow divider to avoid one stopping?) but it’d halve the flow?

The existing hydraulic sideknife is driven from a small dedicated pump with its own reservoir driven off the header drive. It’s a Deutz combine and the dealer’s parts book isn’t obvious.

Any photos or experience welcome!
Thanks

What's the output of the "small" dedicated pump & what are the requirements of the 2 motors ?
If the pump is more than capable of driving both motors I'd be inclined to split the flow as you say via a flow divider.

 

[Mr Happy]

Personally I would use the return flow from the first motor to run the second motor. I can't see there being enough flow to run two hyd motors indepentantly. Without knowing what the motors are I am unable to say if you need to use the drain line port if there is one there

 

[# Robin]

Thanks a lot chaps.
It’s a Bosch 11cc pump which seems to run the knife pretty fast even at engine idle.
No markings on the motors unfortunately, just A and B ports so not sure the seals are bi-directional.
I’ll try splitting the flow first rather than risk buggering them. The motor direct drives the knife-drive so no belts to slip if they’re working hard.
Cheers

 

[Munkul]

I would have thought you would need a case drain line if you were using the main return as a pressure line to feed the second motor. Otherwise the backpressure might kill the seals.

If there is plenty flow at idle it sounds like it should be fine splitting the flow