Any experts here on Bridgeport stepper motors? ( Machine is Series 2 mark 2 MDI ) My "Y" axis motor is buzzing like a good 'un, jerky operation, then overloads the trip, which blows out. Also, gives "Gross position error" even though its not !! Machine unable to be used in this condition. Bob
Bridgeport Stepper motor problem
Nov 23, 2006
30 Replies
John S is the expert I think - no doubt he'll be along in a while !
AWEM
Yes should be a SEM servo. Probably Bosch drives or Drive!
I forget what that Gross Positional error means. I've only seen it when the servo lags terribly from commanded position, like when trying to rapid through a part !
Wayne...
Series 2, Mk2 on steppers with 151 controller ??? Don't sound right to me, I'm no expert but I thought they were on servo's. Details off the plate please.
-- Regards,
John Stevenson Nottingham, England.
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The controller is a TNC 145, I only assume they are steppers, limited knowledge. I'm home know so cant access the plate details. One theory I was offered was that the motor needs cleaning and checking the brushes, if that offers any clues to the motor? Bob
I have had one shed the magnets off the inside when the glue has let go [ no joke - true ] Tends to shag the whole lot up as they are very friable.
If the advise is genuine about the brushes then yes it is a servo.
I may have a motor but it depends on the plate details. You can strip these and clean them. the usual test is to swap leads over to another axis to prove the motor driver combination.
-- Regards,
John Stevenson Nottingham, England.
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Unless the 145 is a retrofit it should have SEM servo motors and Z15 or
16 drives."gross positioning error"means the error is on the machine and not the control.The sem motors have the encoder built in and require a bit of care stripping and rebuilding.It sounds like carbon brush/carbon build up problem but before stripping it check the gibs and slide for mechanical binding.If you take the axis motor off you have to reset the software limits after refitting.It would be worth getting yourself a copy of the maintenance manual,they are on ebay quite often. Mark
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My Series1 mark 1 MDI had SEM motors but he encoder was on the end as normal, tacho is inbuilt. The Encoders on this model were only 125 count and I think analogue.
I have the books on the 145, in fact I have most of the Heidenhain books that the service guys carried.
.-- Regards,
John Stevenson Nottingham, England.
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Most of the Heidenhain manuals including the 145 are available for free download from
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Won`t tell you anything about SEM motors though. Mark.
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Won't argue with you but Heidenhain have dropped a lot of info off their website as they have discontinued support on the older controls.
Only reference I can find to the 100 series is for the124 model.
-- Regards,
John Stevenson Nottingham, England.
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I have 3 manuals for this machine, as suggested, I got them off eBay. The manuals all relate to the series 2 Interact 2, looks identical to mine, except my machine is a series 2 MDI 2. One is a maintenance manual, but doesn't give any detail relating to motor stripping. I will carefully strip the motor Saturday. There does appear to be some sort of encoder on the end of the motor, the thin wire as opposed to the one inch diameter plastic flexible conduit connection. Unless anyone is willing to offer me a "service exchange" ? Thanks for all the help and advice from everyone. Bob
Still there John.Everything from the 111 to 155.Take a bit of finding sometimes. regards, Mark.
I've noticed that. Heidenhain have tried to hide all the useful stuff on their site. Probably a marketing "improvement".
Charles
Unreal happenings !! Turned the mill on today, usual problem, machine alive, but TNC dead. Switched it on and off 20 times, then bingo, life in the TNC. Passed over ref points, then almighty buzzing and shuddering from the "Y" axis motor. Switched off and left it for an hour. Switched back on, and then it acted perfectly apart from a slight buzz/humm from the "Y" axis motor. Does someone up there know how to give me ulcers ?? Bob
Is there enough of a hum for you to be able to play it ?
.-- Regards,
John Stevenson Nottingham, England.
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I think soon that machine will either be at the scrappy or you are going to be a frequent visitor to the Mach3 forum and learning a lot about retrofitting ;)
Depending on your time and inclination retrofitting might be a good step
Wayne....
Think again...................
Well Bob, It was more a suggestion if things really start to get out of hand ;) I had a dead machining centre that I had no hope of getting much support for. About 700 quid later it's now able to run 10 hours a day 7 days a week with no problems whatsover.
If it goes wrong, then I can now get the parts more or less anywhere, and not held hostage by the normal CNC ripoff businesses.
BTW I got a stack of TNC145 cards here somewhere LOL....
Wayne...
I think I am suffering dodgy a connection somewhere in the cabinet since the torturous move it had to my place. A friend has sent a very clever chap to me who is able to strip and rebuild the motors, theoretically. I'm open to offers on any cards !! Bob
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