UBP - Under Bonnet Pump - What it looks like inside - Page 2

James.uk · 20th February 2012, 17:13

Both shafts are indeed screw pumps based on Archimedes principle, although Archimedes encased a single shaft in a tube, but the way this pumps drive is transfered from one shaft to the other reminds me of, and looks like, the idea came from the Geneva movement. Clever innit..

The Geneva movement in the video, the one with the cross, was in fact called a Maltese cross and is used in some time pieces I believe..

...

COLVERT · 20th February 2012, 17:39

The usual failure is that the brushes wear right down. The spring pressure behind the brushes is now so weak that the brushes start to arc against the commutator and burn it away.

It would, as Mike says, be nice to have a photo of the commutator and brushes cos what we have here does not show how the motor failed.

Colvert.

FLYER · 20th February 2012, 17:40

As mike says you will find the copper commutators have worn out , they simply wear so thin they no longer fulfill there function and the pump stops.

COLVERT · 20th February 2012, 18:24

RIK007, you have posted a puzzle. Lol

No sign of failure on any of the parts shown.

T-Cut · 20th February 2012, 18:56

I looks like a combination of an Archimedian Screw and a lobe pump. Unlike Achimedes' device, this system will produce a significant delivery pressure.

Archimedian Pump: http://www.youtube.com/watch?v=5gq3Vm4vifU

Lobe Pump: http://www.youtube.com/watch?v=eDTsk...eature=related

'Pig's Tail' Pump: http://www.youtube.com/watch?feature...&v=j_JRpfmLjkg

TC

James.uk · 21st February 2012, 02:35

Another mystery --- Looking at the way the two shafts are connected from the bottom, the smaller one only makes two full turns for every three made by the larger shaft... But it also looks as though the threaded shafts are enmeshed with each other????? How is that possible???

...

crofts · 21st February 2012, 04:12

Quote:

Originally Posted by COLVERT

The usual failure is that the brushes wear right down. The spring pressure behind the brushes is now so weak that the brushes start to arc against the commutator and burn it away.

It would, as Mike says, be nice to have a photo of the commutator and brushes cos what we have here does not show how the motor failed.

Colvert.

I'm sure you and Mike are correct that is where they fail, same with the in tank pump, I think, and certainly commutator/brushes with the fan motor.

rik007 · 21st February 2012, 09:40

I had a quick look at the pump yesteday, it is difficult to see where the wear may be in the pump. Certainly the two screw pump spindles are tricky to move freely, but I think that may to do with trying to turn them and at the same time stopping them from spinning out of the casing. I have not dismantled the motor any futher, but the bottom of the motor seems to just sit in the plastic base. Having said that when its back together the motor is held failry rigid. I'll get 12v on it at the weekend out of curiosity perhaps.

I rather suspect it may be difficult to see if there is a single point of wear. Looking at the bottom pump machanism I can see that it may well be prone to some wear and have a habit to lock up quite easily, there again it is well lubricated with diesel!

Rich.

rik007 · 21st February 2012, 09:45

Just read Colverts post. I did have a look at the brushes. It doess indeed seem that they have some wear showing and they slide, as normal, under sprung pressure. However haivng said that, it did look like there was perhaps enough of the brush still there to being doing a decent job. I assume if they were so worn perhaps the motor would begin to fail completely?

Will get a better photo ASAP.

R.

HarryM1BYT · 21st February 2012, 09:55

Quote:

Originally Posted by rik007

Just read Colverts post. I did have a look at the brushes. It doess indeed seem that they have some wear showing and they slide, as normal, under sprung pressure. However haivng said that, it did look like there was perhaps enough of the brush still there to being doing a decent job. I assume if they were so worn perhaps the motor would begin to fail completely?

Will get a better photo ASAP.

R.

Inadequate brush contact would show on the commutator as burning and pitting.

Perhaps also check out the other suggestion with regards to the bushes or bearings allowing the armature to touch the field magnets? Tapping the pump might just clear the above long enough to get it to rotate and once in rotation it might hold itself clear enough to run.

20th February 2012, 17:13	#11
James.uk Passed Away 2002 Pale Blue. Rover 75 CDTi Connoisseur auto. 170K miles Join Date: Dec 2008 Location: Near the M67. Posts: 14,509 Thanks: 199 Thanked 585 Times in 397 Posts	Both shafts are indeed screw pumps based on Archimedes principle, although Archimedes encased a single shaft in a tube, but the way this pumps drive is transfered from one shaft to the other reminds me of, and looks like, the idea came from the Geneva movement. Clever innit.. The Geneva movement in the video, the one with the cross, was in fact called a Maltese cross and is used in some time pieces I believe.. ... Last edited by James.uk; 20th February 2012 at 17:18..

20th February 2012, 18:56	#15
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,754 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	I looks like a combination of an Archimedian Screw and a lobe pump. Unlike Achimedes' device, this system will produce a significant delivery pressure. Archimedian Pump: http://www.youtube.com/watch?v=5gq3Vm4vifU Lobe Pump: http://www.youtube.com/watch?v=eDTsk...eature=related 'Pig's Tail' Pump: http://www.youtube.com/watch?feature...&v=j_JRpfmLjkg TC Last edited by T-Cut; 20th February 2012 at 19:02..

21st February 2012, 09:45	#19
rik007 Loves to post Rover 75 Tourer CDT 2002 Join Date: Aug 2011 Location: Cumbria Posts: 404 Thanks: 41 Thanked 7 Times in 7 Posts	Just read Colverts post. I did have a look at the brushes. It doess indeed seem that they have some wear showing and they slide, as normal, under sprung pressure. However haivng said that, it did look like there was perhaps enough of the brush still there to being doing a decent job. I assume if they were so worn perhaps the motor would begin to fail completely? Will get a better photo ASAP. R. Last edited by rik007; 21st February 2012 at 09:46.. Reason: spolling

20th February 2012, 17:39	#12
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	The usual failure is that the brushes wear right down. The spring pressure behind the brushes is now so weak that the brushes start to arc against the commutator and burn it away. It would, as Mike says, be nice to have a photo of the commutator and brushes cos what we have here does not show how the motor failed. Colvert.

20th February 2012, 17:40	#13
FLYER Banned rover75 cdti AUTO TOURER 160 bhp. Join Date: Jul 2010 Location: Glasgow Posts: 35,346 Thanks: 2,985 Thanked 3,685 Times in 2,463 Posts	As mike says you will find the copper commutators have worn out , they simply wear so thin they no longer fulfill there function and the pump stops.

20th February 2012, 18:24	#14
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	RIK007, you have posted a puzzle. Lol No sign of failure on any of the parts shown.

21st February 2012, 02:35	#16
James.uk Passed Away 2002 Pale Blue. Rover 75 CDTi Connoisseur auto. 170K miles Join Date: Dec 2008 Location: Near the M67. Posts: 14,509 Thanks: 199 Thanked 585 Times in 397 Posts	Another mystery --- Looking at the way the two shafts are connected from the bottom, the smaller one only makes two full turns for every three made by the larger shaft... But it also looks as though the threaded shafts are enmeshed with each other????? How is that possible??? ...

21st February 2012, 09:40	#18
rik007 Loves to post Rover 75 Tourer CDT 2002 Join Date: Aug 2011 Location: Cumbria Posts: 404 Thanks: 41 Thanked 7 Times in 7 Posts	I had a quick look at the pump yesteday, it is difficult to see where the wear may be in the pump. Certainly the two screw pump spindles are tricky to move freely, but I think that may to do with trying to turn them and at the same time stopping them from spinning out of the casing. I have not dismantled the motor any futher, but the bottom of the motor seems to just sit in the plastic base. Having said that when its back together the motor is held failry rigid. I'll get 12v on it at the weekend out of curiosity perhaps. I rather suspect it may be difficult to see if there is a single point of wear. Looking at the bottom pump machanism I can see that it may well be prone to some wear and have a habit to lock up quite easily, there again it is well lubricated with diesel! Rich.