30 Year old MOTORUN 3 Phase Static converter

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30 Year old MOTORUN 3 Phase Static converter

This topic has 84 replies, 16 voices, and was last updated 20 December 2024 at 21:55 by John Hinkley.

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14 November 2024 at 00:14 #764357
mr fixit
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@mr-fixit
Hi again, Sorry I sent the wrong picture

This was the picture I had meant to send. Trevor
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14 November 2024 at 11:10 #764408
Baz
Participant
@baz89810
Mr fixit I still have pics and have read your instructions for posting pics and even though anyone can do it, IT DOES NOT WORK ON MY DEVICE. I am using an old iPad that is iOS 12.5.7, my internet banking no longer works on it nor will a lot of sites that I wish to purchase from, PayPal will no longer work either. Every time I log in here I get a banner across the screen saying wplink failed to initialise. I may be old, I am not stupid, I click the picture icon and I get the blank window as you have illustrated but clicking does absolutely nothing, so unless you or somebody else wants to send me a PM with an email address I can send the pics to you are not going to be able to see them.
14 November 2024 at 13:30 #764437
Michael Gilligan
Participant
@michaelgilligan61133
On 14 November 2024 at 11:10 baz Said:

[…] so unless you or somebody else wants to send me a PM with an email address I can send the pics to you are not going to be able to see them.

In the hope of general stress-relief: I am sending you my eMail address

Send me the photos and I will post them.

MichaelG.
14 November 2024 at 13:53 #764442
Michael Gilligan
Participant
@michaelgilligan61133
[ Just a side-note]

This is way beyond my comprehension, but may be of interest to someone cleverer:

https://wordpress.org/support/topic/getting-failed-to-initialize-plugin-wplink/

MichaelG.
14 November 2024 at 15:06 #764451
Michael Gilligan
Participant
@michaelgilligan61133
Herewith six photos … as received from Baz

.

I do hope the forum software can cope

… it seems increasingly flakey at the moment.

MichaelG.

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14 November 2024 at 17:25 #764463
Baz
Participant
@baz89810
Many thanks Michael for posting the pics.
17 November 2024 at 11:21 #764826
mr fixit
Participant
@mr-fixit
HiMichaelG.

Really pleased you found out how easy it is to post your images, They are very interesting to see, thank you for sending them. I see that your converter Circuit looks the same as mine and in excellent condition, you have looked after it well. The paintwork is really good as well, mine has rust on three sides of the box and a rusty lid. Any chance that you could put a continuity meter on the BLACK WIRE OF C3 10Uf Capacitor and see wich switch position thje HP Switch is set on when C3 is connected to the centre pin (WHITE ARROW) IN PICTURES, You will find that the BLACK WIRE goes to one of the (RED ARROW) contacts. I will be very interested to see what you find.

I thought you may have trouble sending a Text email address, the only way I found to do it on Ebay is to write it on an Image then attatch the immage, but do it coloured and small so the AI can’t recognise it. My converter has not changed since my last picture, low priority at the moment, and I like to do things carefully,

Many Thanks MichaelG.
17 November 2024 at 11:45 #764831
Michael Gilligan
Participant
@michaelgilligan61133
On 17 November 2024 at 11:21 mr fixit Said:

HiMichaelG.

Really pleased you found out how easy it is to post your images, They are very interesting to see, thank you for sending them. […]

Can we please all get on the same page

The images are from Baz

.

I was simply a willing courier !

MichaelG.
17 November 2024 at 20:41 #764960
Baz
Participant
@baz89810
Sorry but no chance of any continuity readings, I do mechanical not electrical and I have put the converter back where it belongs and it will take half a day to get it out again, something I am not prepared to do. Many thanks to Michael for putting up my pics. Finally got to bottom of posting pics problem, tried with daughters up to date iPad and tapping in the white oblong box brings up her photos, it doesn’t on mine so the problem must relate to the version of mine which is no longer supported. I must ask Santa for a new iPad and then I can post my own pics.
18 November 2024 at 11:36 #765030
old mart
Participant
@oldmart
Since capacitors are mentioned in this thread, there is a useful website called “badcaps forums” which lists the different makes according to their quality, amongst many other related subjects, and is well worth googling.
18 November 2024 at 22:59 #765196
mr fixit
Participant
@mr-fixit
Hi Baz,

Sorry about the my confusion, I have a very bad memory for names, I just saw your pictures and the name Michael and I never thought to queery it. Pity you did not trace the wire though, to see where it goes you would have to cut off all the cable ties and that is a lot of trouble to go to, never mind. I wonder if the one Noel has just got might be the same

Trevor
19 November 2024 at 18:48 #765402
mr fixit
Participant
@mr-fixit
Hi John,

Not sure if you will ever see this message, I am sure I am typing it in completely the wrong place in a maze of twisty passages, I just wondered what happened to your old Static Converter, have you still got it or did Noel buy it, I would have liked it for my old Harrison Graduate Wood Lathe, the motor is too old to be powered by a Variable Frequency converter.

Trevor
13 December 2024 at 00:28 #770063
noel shelley
Participant
@noelshelley55608
Hi Trevor, I collected The unit from john yesterday. John seems to think it is of 1978. it is an 8Hp unit and looks like 2 4Hp units in one box ( like the picture Clive posted, but 2 transformers ). As John said it has no nice lables just felt tip on the paint of the case. It has 5 switches, Punch/start, boost, normal/high, 2 sets of Hp switches, and timing long or short, this last has me guessing ? I will be testing the caps as if they are over 40 years old they may well be on their last legs. The first task is to draw up a wiring diagram. Noel.
13 December 2024 at 01:03 #770065
noel shelley
Participant
@noelshelley55608
Looking at Clives pictures, the small terminat block screwed to the case has a small RS bridge rectifier on it and the black unit is a rather crude sensing relay, a solenoid coil with a slug that hits the micro switch in front of it which as the current falls off drops back releasing the start caps. I have found a date inside the case feb 1983. The blue cap is an ITT electrolytic, 105-130 uf at 280-350V. Noel.
13 December 2024 at 01:21 #770067
mr fixit
Participant
@mr-fixit
Hi Noel,

The one in Clive’s photo is definitely a “MOTORUN” model I can see that it has identical Component Layout, wiring and set up to mine, I have some MOTORUN brocures in which all the switches are explained ( I think ). I have just been trying to find the Digital Scans but they seem to be lost. I wiill dig out my file tomorrow and re scan any relevant bits for you.

Definitely do a wiring diagram it makes it far easier to re build, mine is still on a bit of wood but it’s working correctly I think, I am going to do a few more tests before putting it back in the case. once in the case it is very difficult to access.

I made a little video of the first test and posted it, but not sure where abouts I posted it to as I can’t find it now.

I tested it on this Bench Grinder -:

Here is a link to the test video -:

https://mail.google.com/mail/u/0?ui=2&ik=245ff8d62a&attid=0.1&permmsgid=msg-a:r311616800327226758&th=1939d8aa320aeb91&view=att&disp=safe&realattid=f_m4d5zyu21&zw

I will get back to you when I find my paperwork.

Trevor
13 December 2024 at 01:37 #770068
mr fixit
Participant
@mr-fixit
Hi Noel,

Is this the picture you are refering to ? I can’t see a Bridge Rectifier in this picture. why you would need any DC Voltages. ?

The black unit you refer to is it that large cylindrical thing on the right hand side.?

Trevor
13 December 2024 at 10:22 #770081
noel shelley
Participant
@noelshelley55608
Hi, Trevor. Thats the picture ! The unit on the right in the 2 clips I take to be the sensing relay. Mine has 3 clips that hold it the right distance from the micro switch. The small chocolate block screwed to the case left of the transformer, above the 3 bolts/nuts – look underneath it, a small RS bridge rectifier lurks Pt No 262-321, and WHY the small pair of 100 uf at 450v caps and a pair of wire wound RS – 156-074 22K resistors in series ? A quick look indicates they are being used for the coil in the contactor. This information is from the 8Hp unit, your components may be different. The 8Hp unit has 2 transformers and 8 Caps. Noel.
13 December 2024 at 13:03 #770110
Robert Atkinson 2
Participant
@robertatkinson2
The bridge rectifier, resistors and two 100uF capacitors form a crude time delay for the start contactor. The contactor does not energise until the capacitor charges.

Robert.
13 December 2024 at 13:14 #770114
noel shelley
Participant
@noelshelley55608
I rather hoped you might comment Robert, thank you. That answers one of my questions and explains why there is a switch labled TIMING that switches in a second 100uf cap . These early MOTORUN converters do seem rather basic/crude, but if it works and has lasted 40 years, proof of pudding Etc.

For those who need to know, these caps are electolytics. Noel.
13 December 2024 at 15:18 #770130
noel shelley
Participant
@noelshelley55608
Trevor, Robert and anybody else who has any info on operating the MOTORUN converters, whilst I have some basic understanding of how they work it would be interesting to read the makers description of how to best use the functions the switches give access to, particularly PUNCH, TIMING and BOOST – the Hp switches are fairly obvious ?

For those with an interest in these things, Graham Astbury book in the Workshop Practice Series No 47 Three Phase Conversion, is interesting, and in it he is against the use of electrolytic caps though the motorun units have them ? WHY ? He says that in circuit for more than a few seconds at 415v ac they will fail. Noel.
14 December 2024 at 00:03 #770189
mr fixit
Participant
@mr-fixit
Hi Everyone,

Motor Run Capacitors are definitely not Electolytic. (see the link below) -:

https://www.google.com/search?client=firefox-b-e&q=are+motor+run+capacitors+electrolytic

I have scanned some MOTORUN information.

In my 2HP there is a small relay that transfers 240 Volts to the Contactor via NC Contacts. There are two Resistors in series with the relay coil, that add up to 25KΩ and a 0.1 µF 1000V. Capacitor also in series. I am certain I have wired it up as it was, and it seems to Start & Run the Bench Grinder ok. BUT I was expecting the small relay to switch off the Start Capacitor when the motor got up to speed. It does not do anything. The coil never gets energised and it remains off with the normally closed contacts feeding 240V to the Contactor which in turn connects the Start Capacitors. consequently the Start Capacitors are never switched out of circuit. This is worrying me.

I soldered a small Neon buld to the NC contacts and it does not go out until I switch off the mains switch

Any thoughts anyone.

Trevor
14 December 2024 at 11:17 #770213
noel shelley
Participant
@noelshelley55608
Just spent 1 hour writing a reply with info to press wrong button and lost the lot ! Bear in mind you are working with 240/415v It sounds as though the sensing/delay circuit is not working – the 2 resistors and the small cap not feeding the relay coil – Cap failed ? Test the circuit. It is interesting that the grinder of 1/2Hp shows the theoretical rotational speed, 3000 rpm, not 2850. More later, Noel
14 December 2024 at 11:29 #770218
Robert Atkinson 2
Participant
@robertatkinson2
Noel said:

“For those with an interest in these things, Graham Astbury book in the Workshop Practice Series No 47 Three Phase Conversion, is interesting, and in it he is against the use of electrolytic caps though the motorun units have them ? WHY ? He says that in circuit for more than a few seconds at 415v ac they will fail.”

The motor capacitors are NOT electrolytic as noted by Noel. The only electrolytics in thes units are those to provide a time delay for the start contactor. These are suppled by a rectifier. You cannot use a standard electrolytic capacitor on AC

Trevor.
It sounds like you have an error in your wiring. Does the small relay have a voltage or part number on it?
I’d expect a diode or bridge rectifier and a larger eclectrolytic capacitor in the circuit.
The motor will run with the start capacitor left connected but it may overheat eventually.

Robert.
14 December 2024 at 13:39 #770241
noel shelley
Participant
@noelshelley55608
The 2 small 100 uf are electrolytic with marked poles BUT the 2x 105 – 130 uf 350V caps are marked as follows:- ITT electrolytic, M28 L1 105 PEO AOO and “intermittent ” The cases have a blue plastic covering though the poles are not marked. Whilst one would not use an electrolytic as a run Cap it seems that it may be using an electrolytic as a start cap ? If Motorun started in 1982, then mine is an early one, Feb 1983

When time permits I will do a diagram of the unit, may be over Christmas. Till later. Noel.
14 December 2024 at 14:01 #770243
mr fixit
Participant
@mr-fixit
Hi All,

i feel a bit stupid now for not doing a thorough wiring check before testing and I had missed out a single wire from the Relay. Now it is working as it should and the Start Capacitor/s is/are switched out after about One Second and the Run Capacitors Switched in. I hope I have not damaged my Bench Grinder Motor running it on the Starter Capacitor I have read somewhere that damage may occur if left too long on the Start Circuit. The Circuit is all finished now and working, just got to get it all into a case.

https://drive.google.com/open?id=1qVUPAmi1VE_ls2qc3CsTZ2wMbNL2XNlJ&usp=gmail

Trevor
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