T and C Grinder Workhead - Drive Motor Replacement.

[Anorak Bob]

After a number of futile attempts at colour matching and painting of the workhead, I gave up and reassembled the the head with its battle scared finish. I had replaced the original integral sealed Timken tapered roller bearings with new but the seal stiction is that high that the 1/30 HP drive motor stalls. The little motor is virtually vibration free and works perfectly when set up for between centres grinding so Dr Bob's and my efforts involved in the conversion of that motor from delta to star are not in vain.

I'm chasing a small 3 phase 4 pole motor not more powerful than a 1/4 horse ( to suit the VFD I have ). Any suggestions?

I don't know if any of the small DC motors available on eBay would be an alternative.

Here are a few photos of the original motor and the workhead.

Bob.

[Stustoys]

Ok I've be scratching my head for awhile and I think I've cracked it. 1/30=1/3?
Do you mean it wont start by itself?

Stuart

[.RC.]

I guess removing the garter springs on the seal to reduce friction will not help, or is possible?

[Anorak Bob]

Ok I've be scratching my head for awhile and I think I've cracked it. 1/30=1/3?
Do you mean it wont start by itself?

Stuart

Not a typo Stu, one thirtieth.

I guess removing the garter springs on the seal to reduce friction will not help, or is possible?

There are not any springs Richard, one lip seals against the cup and the other against the housing. I'll dig up a photo.

Edit - photos here - http://www.woodworkforums.com/showth...45#post1720945 I had better have a hard look at the old bearing to see if there is actually a spring hiding inside!

[Michael G]

Foot mount but any particular frame size preferred Bob?

Michael

[C-47]

Bob,
On my grinder which is probably about the same size as the Hercus, I ended up using a DC motor and controller salvaged from a cactus variable speed Jig saw scrounged from one of the woodworking places in Perth, but that was some years ago now. It has enough grunt to get the thing going and is probably a better option than AC through an inverter. Alan

[Anorak Bob]

Foot mount but any particular frame size preferred Bob?

Michael

I will dig out the tape measure later Michael and furnish you with a few dimensions.

Bob,
On my grinder which is probably about the same size as the Hercus, I ended up using a DC motor and controller salvaged from a cactus variable speed Jig saw scrounged from one of the woodworking places in Perth, but that was some years ago now. It has enough grunt to get the thing going and is probably a better option than AC through an inverter. Alan

Hey Alan,

I just had a quick look at Tony Griffiths' page on Astras and couldn't find a powered workhead. Your innovation?

I have little idea about DC motors and their controls, maybe a site visit sometime?

Bob.

[C-47]

[QUOTE=Anorak Bob;1783447]I will dig out the tape measure later Michael and furnish you with a few dimensions.

Bob, not sure of original set up, but when I got it, the pulleys were there but no motor, so off on a scrounging trip. Welcome to have a gander, I'll get in contact. Alan

[Anorak Bob]

I could well be barking up the wrong tree here. I'm thinking this is a seal and not a motor issue. The workhead spindle should rotate easily enough to follow a guide finger when sharpening cutter flutes. There is no way this will happen with the bearing seals as is. I do recall a slight difference in the physical appearance of the old and new Timken seals.

Steve Durden at FW Hercus sent me a photo of the plaque on one of the work head motors they have on the No.1s in their workshop. Similar tiddler to mine.

BT

IMG_0126 (Large).JPG

[jhovel]

Bob, have a look at this page of Oatleys: http://secure.oatleyelectronics.com//index.php?cPath=53
I have replaced a 1/3Hp AC motor on my wife's felt rolling machine with one of the 100W DC motors (24V model) and it;s been going for about 3 years - pretty well non-stop for 6 to 8 hrs a day. I checked the carbon brushes twice in theat tima and they have barely worn at all. DC motors have their mac torque at start or stall - AC induction motors at full speed only....
I used a $5 Chinese spped controller for that one by Oatleys ave them as well, as you will see.

Other than that, I have a feeling your v-belt is taking all the power your motor can muster. I suggest you also try a round belt - maybe a 3.8Dia urethate belt instead of the V-belt (if that's what I'm seeing).

[Pete F]

After a number of futile attempts at colour matching and painting of the workhead, I gave up and reassembled the the head with its battle scared finish. I had replaced the original integral sealed Timken tapered roller bearings with new but the seal stiction is that high that the 1/30 HP drive motor stalls.
Bob.

Bob I'm not familiar with that setup, but I'm afraid that's not ringing true to me. The bearings should be able to spin relatively freely, even with seals, and I'd be looking at things like shaft alignment etc rather than a bigger motor.

Pete

Edit: ok I just took a look at your original picture you linked to. I'm not sure how the pre-load is set, but check that. I find it difficult to believe seal drag would overwhelm any motor, regardless of how puny, that was designed for a machine.

[simonl]

Bob, have a look at this page of Oatleys: http://secure.oatleyelectronics.com//index.php?cPath=53
I have replaced a 1/3Hp AC motor on my wife's felt rolling machine with one of the 100W DC motors (24V model) and it;s been going for about 3 years - pretty well non-stop for 6 to 8 hrs a day. I checked the carbon brushes twice in theat tima and they have barely worn at all. DC motors have their mac torque at start or stall - AC induction motors at full speed only....
I used a $5 Chinese spped controller for that one by Oatleys ave them as well, as you will see.

Other than that, I have a feeling your v-belt is taking all the power your motor can muster. I suggest you also try a round belt - maybe a 3.8Dia urethate belt instead of the V-belt (if that's what I'm seeing).

Bob,

I may have a spare one of these motors that Joe is talking about. Let me know if you are interested and I'll see if I can find it.

Simon