Member postings for Peter Smith 25

Hi All

I purchased a brand new Crompton Greeves 3 HP 3 phase motor and fitted it to the lathe. The difference was amazing. Very little vibration, and surprisingly, the lathe gearbox in each of it's gears is much quieter. I've left it a while before responding to make sure the problem has gone. So clearly the old motor did not like 3 phase inverters. Thanks all for your help and thoughts, nothing externally to see as to what appeared to be wrong, but obviously electrical black magic at work. Keep up the good work helping each other. Regards Peter

Thanks for your thoughts

I'm also from your area, i was brought up in Bradford, lived in Clayton, and Bingley, before moving to Scarborough in 1996.

Not much in the of industry over here.

All the best

Peter

Hi all

Happy new year

As promised an update on progress with the lathe vibration problem.

Removed the 3hp motor and fitted an abb 1.1 kw 240 volt 3 phase motor.

The vibration felt in the lathe is much reduced and easily liveable with, however when using a tipped tool, taking a decent cut in top gear with the inverter showing 80hz, the lathe slows, so 1.5 hp is not enough to cope with tipped tools.

So, as i'm reluctant to use old second hand motors with the inverter, i've been looking at 2.2kw (3hp) 240v foot mounted 3 phase motors. I understand some cheaper motors are poorer qualty than others. Given the time and effort put into this lathe I'm considering a crompton greeves motor but there coming out at £200 plus vat and carrage.

Can anybody give me advice on how good these motors are or recommend a better ( and preferably cheaper) product

Thanks Peter

Hi Phil.

I live just around the corner from the Dales Factory. The remnents of the workforce move out before the end of this year and it is planned to demolish it and build houses on it.

I've fitted the motor but due to xmas duties, the jobs come to a halt.

I will update everybody when it's back up and running.

Merry Christmas to all, and all the best for 2018.

Best wishes

Peter

Hi Phil and all

Thanks for your input, i won't repeat myself as your ideas have been tested and results noted earlier in this thread.

This afternoon, i removed the motor and wired it up simply sat on the garage floor. The vibrations felt throughout the lathe were now felt in the body of the electric motor. So it appears this motor does not like my inverters.

The 1.5 hp abb motor, shaft height, shaft diameter and key size are the same as the 3hp AEI motor, so no guessing my next move!

I'll keep you informed.

Regards

Peter

Hi IKB

Thanks for your response, the torque control setting was set at 0, so i reset it at 3, tried the lathe, then 6, then 7 then maximum, 10. All made no difference to the the vibration which can be felt wherever you touch the lathe or even the motor body. It isn't a rumble like i found when reversing the winding wires, but is more a tremour. I think i understand your explination, the fault is evident with or without the drive belt fitted and does not change if you take a cut.

As you can probably gather, i'm becoming fed up to say the least of this lathe, i'm quite reasonable as a self taught engineer and only use it for fun, however having to tape the finished work piece to get a decent finish makes me want to look elsewere for a hobby.

Thanks again for your thoughts

Peter

Hi Brian

I checked the rotor assembly balance as in desperation i changed the motor bearings. They were very good and a good fit in the housings. With no play when assembled and the rotor spin freely by hand. I split open the old bearings and the were also in good condition.

Thanks for your thoughts

Peter

Hi all

As an experiment, i changed the inverter torque control settings to 3,7, and max 10. None of them made a scrap of difference, so that's it for this motor. Tomorrow i'll pull the lathe away from the wall, (no mean feat) and swope the motor for the 1.5 hp.

I'll let you know the outcome.

All the best

Peter

Hi Isimbard Brunel

Thanks for your input.

Would altering the torque setting (F13 on my inverter) effect the vibration which is evident at all motor speeds, with and without the drive belt fitted? The vibration is evident running the lathe, taking light cuts or even cuts of 100 thou per side (which it will do without much problem).

Thanks

Peter

Hi Mike and guys

Sorry i've tried to upload photos but failed miserable, so the motor plate info is

Type D90L

V220/250-380/440

A 8.7/5 3HP DE 125P

1410 RPM HZ 50 IC1258

Inverter info is not listed in the printed sheets but on the side of the inverter is a sticker with

Input:AC 1PH 200-240V 50/60HZ 20A

Output:AC 3PH 0-240V 0-200HZ 3HP.

Hope this helps

Regards

Peter

Hi All

Thanks to Mike and Peak4, very well explained.

I've just come out of the garage after working in the base of the lathe changing around the wiring as suggested.

On each of the winding wire changes the motor ran much slower, rougher and grumbled as if it had a knackered gearbox.

So I think the wiring was originally correct. As you can imaging after all i have done to this lathe, i think i would be better off sat in the pub with a glass of real ale!

I'll now have the day off it and i think change the motor which brings me back to, do you think 1 and a 1/2 hp motor is adequate for the lathe and if not what would you fit.

Thanks again for your help, and have a good weekend

Peter

Edited By Peter Smith 25 on 15/12/2017 10:57:40

Hi Mike.

Sorry to ask stupid questions, do you mean swoping the 3 inverter output wires around, as i initially did this to correct the rotation of the motor (swoped two of the three wires). I have wired the inverter input control into the lathe switch gear. As such the start, stop and forward/reverse switches on the lathe control the input switches on the inverter. The only external change to the lathe is the addition on a 10k pot.

Regards Peter

Hi all

For info the windings have letters and numbers on each. I have connected

B2 to C1,

A2 to B1 and

A1 to C2.

Each of the inverter utput wires connects to each of these pairs. Does this appear to be correct?

Thanks Peter.

Hi all.

Just a quick up date.

Removed the motor wires from the invertor. Run a new feed wire from the inverter to a used ABB 1.1 kw 3 phase motor. The motor was sat unbolted on the cross slide and the inverter turned on. Motor ran quickly up to speed with negligable noise and vibration (only what i expect from an electric motor) whilst running no vibration evident in any part of the lathe. Removed the new wires from the ABB motor and connected them to the lathe motor. Turned on inverter. Lathe and motor body vibrated. For some reason the motor and inverter do not appear to be compatable. As the motor has misbehaved with two inverters, then it appears to be time to replace the motor

So, i propose to take off the original 3hp motor and replace it with the ABB 1.5 hp motor. Next question, do you think the lower powered motor will be man enough to run the Colchester Student. It is not used for production work just making parts for my motor bike etc. Or can anybody recommend a source for aquiring a suitable motor and the what size should i use?

Thanks for your help

Peter

Hi guys thanks for your response.

Just for info, when i stripped the electric motor i checked the rotor with the pulley attached upon a crankshaft balancing jig i made to balancce my motorbike crank. It appeared to be statically in balance. The vibration is evident in the lathe with the drive belt disconnected, as such only themotor spins. It has no problems with rotational speed or power ( heavy cuts can be taken without noticable reduction in chuck speed), as such i don't think a phase is low or down. The vibration is not a glaring one but if you place your hand on the tail stock, apron, base or head stock the vibration can be felt (with or wothout the drive belt on). My next step is to change the wiring fromthe invertor to the motor, and i have a spare 1.5hp 3 phase motor. I will connect this in place of the lathe motor but let it spin on the floor. If this one vibrates....... anybody want to buy a colchester lathe!

Hi All

Just joined the forum after my friend started this thread on my behalf.

The Invertor was purchased from ebay (last year) and was sold as a 2.2 KW VAT20 GE U20N 2K25. It looks identical to a Teco MiniCom E2-203-HF 2.2KW which direct drives sell (but much cheaper. I have in the past purchased a Teco Invertor from Direct drives and apart from the name I cannot find any difference, even the manual instructions and settings are the same.

I have carefully wired up the invertor, and have (amongst other setting changes) changed the F12 carrier frenquency settings across the whole range. F1,2,3,4, and 6 make the motor whistle,additionally in these settings and the other settings, the motor has a slight rumble and vibration which can be felt throughout the lathe. Also the turned finish both with tipped tools and sharp hss is poor.The Lathe is a 1977 Colchester Student, and the motor is a 3hp AEI Kapax. In desperation I have changed the bearings (waist of time), windings all measured the same and were like new. This is the second invertor fitted to this lathe the previous one also made the motor whistle but it was much worse and was only useable in the highest Carrier Frequency setting. The vibration is evident with the drive belt disconnected. Increasing the HZ up to approx. 75 is where the motor is happiest. Any Ideas?