Schaublin 135 - Help upgrading electrical system

[ballen]

Hi Mark,

if a replacement rectifier is needed this is both easy and inexpensive.

Please confirm that when you wrote "the electromagnet works" what you mean is "when I connected the electromagnet in the brake to a benchtop power supply it worked correctly".

Could you remind me what electromagnet operating voltage was that you tested with? Was that value marked on the magnet or did you get it from the supplier of the brake?

Cheers,
Bruce

 

[ballen]

Marc, if you look at the wiring diagram that you posted here (135-99023.pdf) you can see how the transformer (m4 in the diagram) is powered.

On the left is the power input, through the cables RST which carry the three phases. Often these are labeled L1, L2, L3. This passes through a disconnect switch a1.

This switch probably has two purposes. First, it disconnects all power from the machine for service work and to "put it to bed at night". Second, it may be interlocked with the electrical box cover, and unless it is turned off, the cover can not be removed. For checking the operation of the rectifier, this switch must be ON.

When this switch is in the on position, the primary side of the transformer m4 (the coil on the left in the diagram) is powered, and so there should be both AC and DC voltage present on the rectifier, as described above. Nothing else needs to be turned on.

(The transformer low voltage secondary provides power for all of the control circuitry, so the transformer is turned on whenever the machine is powered.)

Cheers,
Bruce

PS: looking ahead a bit, the circuitry for the brake shows two electromagnetic parts. S1 is the electromagnetic brake itself, the thing that you tested in a previous post. S2 is a relay or solonoid or some other type of electromagnet. Any idea what its purpose is?

 

[marcsO]

OK so have had a closer look at this rectifier and the

Hi Mark,

if a replacement rectifier is needed this is both easy and inexpensive.

Please confirm that when you wrote "the electromagnet works" what you mean is "when I connected the electromagnet in the brake to a benchtop power supply it worked correctly".

Could you remind me what electromagnet operating voltage was that you tested with? Was that value marked on the magnet or did you get it from the supplier of the brake?

Cheers,
Bruce

It was checked with the manufacturer, I spoke to a guy who had worked for Warner before it was taken over and he remembered the brake system they made for Schaublin and the fact they used a 'new' plastic material for the bushes which sadly according to him did not last as they expected and suggested making them from brass as this was the original material used and to him the best. This is what I did.

Voltage from memory was 20-30v to test - DC.

 

[ballen]

Marc,

in the message above you wrote "OK so have had a closer look at this rectifier and the". Was something lost there?

By the way, it appears that right after the rectifier are two fuses (E2 in the diagram). If either one is blown, replacing it should fix things. But I still suggest working step by step as described above. Newtonian reductionism is very effective for machine tools.

Cheers,
Bruce

 

[marcsO]

Had a look at the rectifier, it does seem original after all as its made up of a series of plates slid over an insulated central bolt which clamps the plates together. There are four connections and the last one nearest the front is linked with a wire back to the first connection on the device, this can just be seen in picture 1 & 2.

Did turn on the main power switch and checked rail pins 17 & 18 which from my basic knowledge seemed to be where the output from the rectifier terminated before they went to the brake - no sign of any DC voltage at these pins.

 

[marcsO]

Ops my error should check 18 & 19 and not 17!

Off to the workshop .........

 

[ballen]

I remember taking apart old TV sets as a kid 50 years ago and seeing these.

Selenium rectifier - Wikipedia

en.wikipedia.org

Are there four of them? I suggest that we simply replace this with a much better modern part that costs a couple of bucks. But let's first try and get it working "as is".

Anyway, next step is, identify the two wires coming from the transformer secondary. You should measure 20 or 30 VAC across them when the transformer is turned on.

Pins 17, 18 and 19 are way downstream from where you should be looking. Just figure out which of the two wires going to the rectifier comes from the transformer. They may have the same color since the AC has no polarity.

PS:

Figure 5-5 of this link https://www.industrial-electronics.com/sams_metallic_5.html
might show which connections are AC and which are DC. Does yours have external wiring that matches this? If so, there will be five connection points in the stack, and the outmost two (labeled "+" in the figure) will be connected together with a jumper wire.

If it matches, then use a multimeter to measure the AC and the DC voltage across the terminals labeled "AC" and to measure the AC and DC voltage across the terminals labeled "+/-" and report back here.

PPS: Looking more closely at your final post and final photo above, I can see the jumper wire which you mentioned and which is the same as in the diagram.

So, one set of connections, are the middle connection and the (jumpered) top/bottom connection. This set of connections will be either the AC or DC one, depending upon how the stack is organized. The other set of connections (not end, not middle) are the DC or AC one.

For clarity here, label the connections in the stack from Front to Back by A,B,C,D,E.

A and E are connected by a jumper.

You need to measure AC and DC voltage between A and C, and between B and D, and report those here.

 

[Peter from Holland]

Whenever looking for faults in a electrical system of which I have a electrical diagram I always look at it and try to understand how it works a bit Only the vertical line where the fault is to start Then look for the easy spots to measure eighter Volts or Ohms The terminalblock is such a spot Numbers are in the diagram And it is easy accesabel
It is good to know that the diagram represents the situation without power
In this situation I would have applied power and measure terminals 18 and 19 for DC voltage Somewhere in the middle Taking bigger steps that way So I do it different then Bruce in this regard
If we have DC voltage over there we go downstream If not upstream

Downstream the next step for me would be to see if d2 gets activated If that does not get activated the fault is in another line So every observation dictates the next step that way
Another thing I do when measuring Ohms for a coil for example I disconnect one wire to make sure I only measure through the coil So if I want to see if the coil of d2 is oke I measure ohms trough d2 with one wire of the coil disconnected

Peter

 

[ballen]

Hi Peter,

your method also sounds good, and if you have the time to walk Marc through it, please go ahead.

Any idea what R1 and R2 are? Variable resistors for setting the braking force? How about s1 and s2? I assume that s1 represents the brake that Marc has already tested. But what about s2? It looks like a solenoid, but I have no idea what it's for. Do you know?

(The wiring diagram, as opposed to the circuit diagram, shows that s2 is some type of security system. It seems to be linked to a switch, b10, which is not shown on the circuit diagram. Do you understand what that is? I think it operates when the brake is NOT in operation.)

Cheers,
Bruce

EDIT: Found it here on page 4:

http://www.swissmachines.ch/files/Catalogue%20Schaublin%20135.PDF

Dispositif de sécurité par électro-aimant du réducteur à engrenages. Le levier ne peut être manæuvré qu'à l'arrêt de la broche.

English translation, roughly: "Security device using a solenoid for the gear reduction lever. The lever can only be operated when the spindle is stopped."

That's the purpose of s2.

 

[Peter from Holland]

Hi Peter,

your method also sounds good, and if you have the time to walk Marc through it, please go ahead.

Any idea what R1 and R2 are? Variable resistors for setting the braking force? How about s1 and s2? I assume that s1 represents the brake that Marc has already tested. But what about s2? It looks like a solenoid, but I have no idea what it's for. Do you know?

(The wiring diagram, as opposed to the circuit diagram, shows that s2 is some type of security system. It seems to be linked to a switch, b10, which is not shown on the circuit diagram. Do you understand what that is? I think it operates when the brake is NOT in operation.)

Cheers,
Bruce

EDIT: Found it here on page 4:

http://www.swissmachines.ch/files/Catalogue%20Schaublin%20135.PDF

Dispositif de sécurité par électro-aimant du réducteur à engrenages. Le levier ne peut être manæuvré qu'à l'arrêt de la broche.

English translation, roughly: "Security device using a solenoid for the gear reduction lever. The lever can only be operated when the spindle is stopped."

That's the purpose of s2.

Bruce
You are doing fine I take bigger steps perhaps But if that does not come with a solution I go back your way
I noticed a irregulairity between the wiring and logic diagram as well The numbers for the cable terminals do not match it seems
For example On the cable diagram the brake (frein) is on 50 and 51 and R2 is missing But on the logic diagram on 16-17

No answer from Mark yet if we have DC on 18 and 19 though

But
If 18-19 have DC s2 must function
Next question would be Is d2 switching???

Pull it out of its socket and swap it with d3 perhaps It probably is the same

Peter

 

[marcsO]

Hi back on the trail now, had a busy day.

This is r1



This is r2



I am going to see if I can mark up the rectifier ABCDE and check for AC voltage at AC and DC at BD and ping these on the forum in a short while.

Bruce also mentioned that there are two fuses e2 after the rectifier, in reality they appear to be a bank of 3 contactors with another bank of three marked e1 above, are these 'fuses' as they 'clack' when the motor is switched on and when the high speed option is demanded there is what sounds like a double 'clack' as if something is connecting and then releasing immediately after.

When I spoke to the manufacturer of the phase convertor he said that maybe the draw from the motor was large enough to make the voltage drop enough to release the contactor and hence not spin the higher speed.

This is what looks like e2



For reference this is d3

 

[ballen]

OK, interesting. The red component is not a resistor and not original. It is a metal oxide varistor, put there by a later owner to prevent damage to the rectifier from voltage surges caused when the electromagnet is switched off. A very good idea. If you can find R2 it would be good to see.

R1 is an adjustable resistor, set to 58 ohms. I don't yet understand its purpose. The circuit diagram also shows a fixed electrolytic capacitor, labeled k1. A photo of that would also be useful.

Marc, you wrote that e2 are not fuses, but then sent a picture where e2 was a bank of three fuses. Could you please edit your post for clarity about this point?

 

[marcsO]

I was told the two banks of three 'magnetic contactors' e2 and e1 are electromagnetic switches and not a fuse, are you saying these items in the picture are some elaborate fuse?

Will check to see if I can find r2, r1 as I understand is a variable resistor used to adjust the motor brake.

Will also see if I can find k1

 

[ballen]

This is what looks like e2

These six white objects are screw-in fuse holders, with replaceable cartridge fuses inside. Based on the circuit diagram, I think three are for the input 3-phase power, one is for the transformer secondary, and two are for the DC circuit.

I suggest you unscrew them, pull the fuse from inside, and write its current rating onto the white ceramic holder with a Sharpie marker. I'd also write these onto the transparent plastic box. Then take another photo, both for your records and to post here. Three of the fuses will be identical and high current. These are for the input 3-phase power. I am guessing they are the top three, since they have identical black wiring. The other three fuses, for the transformer secondary will be lower current.

 

[ballen]

I was told the two banks of three 'magnetic contactors' e2 and e1 are electromagnetic switches and not a fuse, are you saying these items in the picture are some elaborate fuse?

E1 and E2 are just normal fuses: thin pieces of wire that melt if too much current flows through.

E3 and E4 are motor protectors. These protect the coolant pump and the lubrication pump. These have a bimetal strip which senses the current flow through each of the three phases. If too much current flows, the protector "pops" and turns off current to the motor and power to the contactors that control the motors. They must be manually reset to restart the motors.

The main spindle motor is only protected by the fuses E1.

Finally there is an overcurrent protection device E5 that turns off everything if there is too much current being drawn from the transformer secondary.

C1 and C3 are the contactors (relays) that control the spindle motor low-speed windings, and C2 and C4 are contacters that control the spindle motor high-speed windings.

 

[ballen]

Something I realized: your two electrical diagrams are not compatible. The one dated 1970 shows that the main power protection is via a fuse e1. The one dated 1973 shows that the main power protection is via a circuit breaker e5. From the photo you sent showing the bank of 6 fuses, I would suppose that your machine is closer to the 1970 drawing.

 

[marcsO]

These six white objects are screw-in fuse holders, with replaceable cartridge fuses inside. Based on the circuit diagram, I think three are for the input 3-phase power, one is for the transformer secondary, and two are for the DC circuit.

I suggest you unscrew them, pull the fuse from inside, and write its current rating onto the white ceramic holder with a Sharpie marker. I'd also write these onto the transparent plastic box. Then take another photo, both for your records and to post here. Three of the fuses will be identical and high current. These are for the input 3-phase power. I am guessing they are the top three, since they have identical black wiring. The other three fuses, for the transformer secondary will be lower current.

Pulled all the fuses one by one and checked them, all are good, top three are as you say for the incoming power and are rated at 25A, the bottom row are not marked with current capacity so will get out the magnifying glass and see if its marked on the casing.

Either way these are all good and learnt what old fuse holders look like, certainly on the side of 'over engineered' IMO

 

[marcsO]

Top fuse set labelled with 25A



I have removed and taken a closer look at the lower fuses and attached pictures which seem to indicate 6/500 which I am guessing means 6A 500V



I have also taken a picture of the lower fuse holder with fuses removed and cover off and it looks like the only coloured wires used on this panel are red and blue. The rectifier has blue and grey wires attached to it so can I assume the rectifier feed to the fuses is likely to be supplied on the blue wire connections? If so I could also test for DC voltage at the fuse holder?

 

[marcsO]

Went ahead and checked DC voltage on the two single top feeds on the blue wires into the fuse holder - 14.8V DC
When I fitted the fuses and checked the voltage output after the fuse the result was 11.9V DC

Is this in the right parameters as was expecting the feed voltage from the rectifier to be higher and quite alarmed at the voltage drop when the fuses are fitted.

Await feedback and next action....

May try to check the two grey wires now on the rectifier as from deduction it should mean they are the AC feeds from the transformer, will post any results.

 

[marcsO]

Grey wire connections on the rectifier are showing 32.2V AC

Also now have 11.9V DC at terminals 18 & 19 when motor not running.