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Schaublin 135 - Help upgrading electrical system

Am I right in saying that from the schematic terminal 60 from b1 terminates on c3/11?
Yes, if we can trust the schematic, this is correct.

If so can I check the VAC across 55 (bottom terminal block) & c3/11 to obtain the reading required?
Assuming that the "55" next to the b1 switch contact is connected to 55 on the terminal block, then yes. Tracing 55, it also appears to connect to d1/U. So you can also check d1/U to c3/11.

(Within reason, try and do sanity checks and trace wires, because as you have seen, we can not always trust that the schematic and drawings are correct.)

I strongly recommend that you print out a copy of the schematic and make notes on it. For example identify the contactors and switches. Identify wire colors and locations. Put notes about how things work and corrections to the schematic where needed.

Alternatively, make a copy of the original PDF file and then annotate that.

PS there is no 60 on the terminal block and also looking at the schematic it looks like these are simply b1 numbering, if you check terminal 55 from b1 this goes straight to 51 as a feed so maybe I should check 51 across c3/11 for a VAC reading when tripped?

I have forgotten which schematic is correct. Does it go to 51 or to 52?

In any case, you have the correct idea. Use the schematic to locate an accessible wire which is connected to the switch contact that you want to probe.

d1 and d2 coils are 10A while c1-4 are 16A coils so wont fit sadly.
I will check T/W as an alternative as this looks to be the same visually as RU and report.
Yes, the pairs R - U, S - V and T - W are the three normally open (NO) contacts on a three phase contactor. They are equivalent to one another.

Note that RST/UVW is the Swiss labelling, also used in some parts of Europe. In the USA and some other countries you are more likely to find L1 L2 and L3 for inputs and T1, T2 and T3 as the outputs. L means "line" and the use of the three numbers emphasises the symmetry or equivalents of the three contact pairs.

Assuming a 'soft start' which I have coming will help matters how and where should it be installed?
Please post a picture of the soft starter showing the connections and I'll provide an answer. Once I have done that, let's ask Peter to confirm that he agrees.
 
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These arrived yesterday, one or two in the place of the current one?

If two assume in parallel?
IMG_5357.JPG
 
Put two in parallel with the current one. So you have three in parallel. Have you replaced the capacitor with the new one? Once your new d2 coil is ready, we can test and if needed adjust the brake.
 
55 - c3/11 when tripped with power still on reads 37 VAC
d1/U - c3/11 when tripped with power still on reads 6 VAC

Swapped over the R/U connections at d1 to the T/W connections and no change to tripping (still does)

Not changed the capacitor - need to order one as it slipped through the net.

This is the soft start device
IMG_5358.JPGIMG_5359.JPGIMG_5360.JPG
 
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A thought.. (yes I know I have too many!)

The system which uses the carriage lever to function up to 5 modes depending on where the round dial is positioned, develops slop over time which impacts selecting the ranges accurately.

So how much work would be involved wiring wise to do the following:

Make the carriage lever a simple on/off only lever connected to a new on/off master switch attached to the current linkage and either use the existing b1 switch relocated to sit behind where the round dial is currently and add a selector knob rather than the current cam plate on the switch and a new machined face plate suitably marked up which allows you to turn the knob to either forward high or low or reverse high and low? If b1 cannot be used a new 4 position switch could easily be bought......

I'm not a fan of the current system and whilst its not original to change things I really don't think it would be a bad conversion and if original parts are kept it could be returned if needed to 'as original' if that was a deal breaker.
 
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Marc, not sure about replacing the switch
55 - c3/11 when tripped with power still on reads 37 VAC
d1/U - c3/11 when tripped with power still on reads 6 VAC
This does not make sense. According to the schematic, 55 is connected to d1/U. So the two readings above should be the same.

Swapped over the R/U connections at d1 to the T/W connections and no change to tripping (still does)
OK, that was a long shot, not surprising that it did not fix the issue. I suggest you return the connections to R/U just to be in agreement with the schematic.
Not changed the capacitor - need to order one as it slipped through the net.
Please replace, that's easy and cheap, and electrolytic capacitors do age. Mind the polarity when you replace it.


This is the soft start device
View attachment 404841

Wire as follows:

(a) L1/T1, L2/T2 and L3/T3 go in series with either the R/S/T or U/V/W terminals of contactor c4. So instead of the current flowing from c4 to the motor, it flows from c4 to soft starter to motor.

(b) Connect pins A1 and A2 to the transformer secondary after the power fuses e2. So terminals 53 and 50 according to one schematic. Check with a voltmeter first that you have 250VAC there whenever the lathe is turned on.

A1 should go to terminal 53
A2 should go to terminal 50

(c) 1 should go to c3/12

This way, when the high speed motor is turned on, the contact pair c3/11 and c3/12 are connected to the power line 53, which turns on the soft start. That then ramps up the current through L1/T1, L2/T2 and L3/T3.

For initial testing purposes, leave the top control of the soft start (ramp up time) at the current 5 secs. Put the middle control (start voltage) at the minimum setting. Put the third control (ramp down time) at the minimum value. If this works, then decrease the ramp up time if the 5 seconds seems too long, and increase the start voltage somewhat. Of course if you start to trip the d1 contactor, then revert to values that do not cause any tripping.

I suggest we have Peter Veltmann check this before you go ahead. I have VFD experience but not soft-starter experience. Can you sent a private note to Peter and ask him to look at this?

(Peter: schematic is below. c4 is the contactor for the motor high speed, so we need to put the slow-starter in series with that. Contactor c3 pins 11/12 provide the current which closes c4 and which I also want to use to trigger the slow start. We can not use the soft starter to completely replace c4, because c4 has a normally closed NC auxiliary contact, and the soft starter has only normally open NO auxiliary contacts.)

Screenshot 2023-08-10 at 16.32.56.png
 
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I did use it once on a lathe So no expert what so ever
Probably you can even replace C4 with a soft starter. For some reasson I did not do that at the time. IIRC the thermal overload did not fit the softstarter
But anyway you have to pick one with the right controle voltage (voltage between a1 and a2 on C4. 24Volts??? )


Perhaps you could even use it for both low and high speed You have to put it above C1 and C2 then
No harm in trying I think Optimize it for high speed
I do not know if you can set it properly for both speeds thoygh If set incorrect the motor can start to stutter at speedup
The settings also may differ with a heavy item in the chuck
But someone more knowligable should shim in here if you want further advice


Peter
 
I did use it once on a lathe So no expert what so ever
IMO this is pretty low-risk. But two sets of eyes are better than one.
Probably you can even replace C4 with a soft starter.
Only if the soft starter has an NC aux contact. The one that Marc got only has NO aux contacts.

But anyway you have to pick one with the right controle voltage (voltage between a1 and a2 on C4. 24Volts??? )
This lathe uses a 255 VAC (!!!) control voltage, the transformer secondary. The soft starter control voltage is 230V with a 10% allowance so 255 should be OK.

Perhaps you could even use it for both low and high speed You have to put it above C1 and C2 then
Yes, I guess in principle that is possible. But at least to start off I thought it was better to just mess with the high speed motor winding current and leave the low speed circuit untouched.

But someone more knowligable should shim in here if you want further advice

OK, let's see if someone reading this thread wants to give an opinion.

Meanwhile, does this make sense to you?

(1) The soft starter gets power from the control trafo at the soft starter power inputs A1/A2, so A1 to terminal 53 and A2 to terminal 50?
(2) The soft starter "start" command terminal 1 should be wired to c3/12.
So when c3 opens (for motor high speed) this connects c3/12 to 53 and hence to A1, giving the start control signal.
 
Hi both appreciate the collaboration.

There is ample room in the electronics cabinet for the soft starter as well as the other electronics, also more space if other items are required to complete this task, so don't be concerned.

Winding the coil is proving a little tricky as the wire keeps snapping, its thin at 0.14mm (34 AWG), managed 20 mins of winding earlier on the lathe and got about 1/3 of the way and it broke so will unwind and try again :Yawn:
 
Marc: check resistance of the broken wire to be sure you have the length right. 1/3 of the length should give you about 1/3 of the total resistance that you are aiming for.

Peter: if you think that is a better approach then we could re-use c4 as the auxiliary relay c5. In fact all that means is that we re-route the RST/UVW power wiring to eliminate c4.

Marc: I'll produce a modified schematic later today or tomorrow morning, don't have time to do it now. Suggest you concentrate your efforts on winding a new d2 coil. You can also solder the broken wire, paint some epoxy over the solder joint to insulate it, and just keep on winding.
 
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This was the set up in the lathe, simple format using a boring bar to hold the wire reel and found a plastic tube which was flexible enough to push into the end of the coil holder, think it was a drill bit merchandising packet.

First attempt resulted in a broken wire after a few minutes winding, think the brush handle I was using to guide the wire was rough and the wire snagged.

Second attempt was better and got a decent wind on, sadly after removing from the lathe and then handling the coil to prepare for testing the broken section broke off again, seems the methacrylate glue does not like this plastic or bakelite material. Stripped all the wire off and used superglue and a few layers of fine glass fibre cloth wicked with CA - this method I have used many times when building rc jets and its very strong. The cloth overlaps the broken joints inside and outside so hope this achieves my repair goals better!

Third attempt got a good wind on, thought I had plenty but when removed and checked the Ω reading it was .376 kΩ verses the other original coil which was .557 kΩ so guess I need to load up the coil more to achieve a better match? Assume this is not sufficient?

Couple of things, as the wire is thin it's very hard to remove the coating to get to bare wire without snapping off the wire, tried a fine sanding block between my thumb but this did not remove the coating, used a scalpel blade and my thumb again and this had some success but not easy to remove all round - is there a better way, a chemical like acetone or maybe heat etc? Ultimately will need to clean off the wire to allow soldering to tabs when the coil is wound more so help is appreciated as to best practice.

I will have to start a new coil anyway as soldering this wire together is almost impossible so will remove and then solder the starting end before winding so only have the tail to do which is more accessible once wound and if its breaks I can keep on unwinding it as it won't make any difference to the Ω value.

Here is the set up..
IMG_5362.JPGIMG_5363.JPG
 
Winding the coil is proving a little tricky as the wire keeps snapping, its thin at 0.14mm (34 AWG), managed 20 mins of winding earlier on the lathe and got about 1/3 of the way and it broke so will unwind and try again :Yawn:
Winding a coil for a contacter??
I new it was a fun project But even a fun project has its limitations
D2 it was???
The contacts probbably are bad also as it is switching DC
The problem with this contactor is it needs 4 main contacts Hard to find I thought Not so.This 20amps schould do
https://nl.rs-online.com/web/p/contactors/1884691?gb=sYou can put a additional auxillary contact on top
Any brand works for this Even a used one would be better IMHO as the one you rewind
Looking at the diagram one could even put the contactor before the rectifier There it is AC Much friendlier on the contactor
Peter
 
Marc, go ahead and test your 376 ohm contactor coil. It will either work fine or it will burn out in a few seconds and then you try again or buy another contactor or the right coil from the place in the USA that has them. More important than the resistance is the inductance when mounted on the contactor core, and you don't have the tools to measure that. So just try it. Cheers, Bruce

PS: to solder the wire, first use a razor blade or xacto knife to scrape off the vanish, or use a drop of paint stripper.
 
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Marc, here is my suggested wiring for the slow starter SS. It is not ideal but should enable testing. If this solves the high speed tripping problem then we might improve it somewhat. With this configuration the slow starter replaces the RST/UVW contacts of c4. However you must not remove c4, because its remaining contacts AB (coil) and 11/12 (NC) are needed. If this solves the tripping problem then we might rewire c4 or replace it with a simpler relay as Peter suggests.

STUDY THE DIAGRAM BELOW CAREFULLY BEFORE YOU START MODIFYING THE WIRING. IF YOU HAVE QUESTIONS, OR SOMETHING SEEMS UNCLEAR, ASK FIRST. PHOTOGRAPH/LABEL/DOCUMENT THE EXISTING SYSTEM WELL ENOUGH THAT YOU CAN RETURN IT TO THE ORIGINAL STATE WITHOUT ERRORS. ABOVE ALL, CHECK YOUR WORK SEVERAL TIMES BEFORE APPLYING POWER. 400V ELECTRICAL SYSTEMS DO NOT FORGIVE MISTAKES OR SLOPPY WORK.

Screenshot 2023-08-12 at 19.32.49.png
 

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Finally wound the coil to 586Ω which is between the suggested 500-600 range, epoxied in the soldered wire ends where they meet the tabs and all still checks out.

Next stage is to fibreglass wrap the exposed coil wire using thin CA which wicks into the cloth very easily and should give a proactive thin coat to the coil wire.

Bruce will study and come back with any questions, much appreciated.

IMG_5365.JPGIMG_5366.JPG
 
Coil looks good, fingers crossed that it works correctly.

Marc, before you proceed further, could you tell me what the voltage on your control system is? This is the voltage from the secondary of your control transformer, measured between terminal block contacts 50 and 53, or across any contactor coil when the contactor is closed. From what you have written earlier, it seems that this is about 250VAC. If that's right, I think it's on the high side and might be easy to reduce to 220-230VAC. That would be good for all of the control electronics. A too high control voltage is probably the reason that the d2 coil burned out.

Could you take a photo of the connections on the control transformer, particularly on the primary side and post here? I suspect that this might be a transformer where there are multiple taps on the primary winding. If that's the case, I bet that it is wired to the 380V inputs and should instead be wired to the 415V inputs, which will drop your secondary voltage by 8% to 230V. If I am right about the multiple taps, then it will take you about five minutes with a screwdriver to move the wire from the incorrect tap terminal to the correct one.
 
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