Variable speed controller on a Hegner multicut 2S

[Myfordman]

Thank you for that generous offer Ray.
alternatively if their price is high, I might be able to sort yours out if you send me the motor and controller. Having done a bit of research I’m feeling pretty confident that I will be able to analyse the problem. About the only part that might be less easy to source is the tachometer device should that turn out to be faulty.
Let me know what you decide when you get the pcb price.

 

[scrimper]

I have owned a Hegner for over 20 years and have done a couple of videos on their use etc. the only thing that went wrong with mine so far is that cheaply made little on off switch which Hegner wanted to charge £24 for but which is a bog standard switch widely available for around £1.


Now I have spent most of my working life with electric motors and machinery but the problem is that Hegners use Induction motors , which is good because they are very reliable and only very rarely give any problems.

The problem with induction motors is with speed control, it's not straightforward, most machines with variable speed controllers use the series wound/carbon brush type motor which can be built in when the device is manufactured or can be added later with hardly any problems. You can't do this with induction motors and those motors such as Hegner use are special and to be honest I know very little about the way they are controlled.

Normal (single phase) induction motors and series wound motors have mostly just have two wires supplying current to them (+Earth) but these special motors have more wires and their speed control is quite complicated which I know little about because my Hegner is the only machine/appliance that I have come across with a speed controlled induction motor.

In 40+working with motors years the only ones that I have experienced with speed control have been universal or carbon brush type motors which can easily be controlled with simple electronics such as thyristor or triac control. The Hegner speed control is quite different and I have practically zero knowledge of how it all works.

The price Hegner charges for a new motor is quite ridiculous but I would doubt that your motor itself is faulty more likely something external to it such as the capacitor/wiring or controller. There is some information on the net about single phase induction motor speed control but it is mostly very technical.

As I say I would be very surprised if the actual motor itself is faulty, they are very reliable and during 1000's of motor faults I have been involved with only about 3 or 4 induction motors had burnt out or faulty windings and they were due to external faults such as a seized gearbox etc.

If you do sort it out I would be interested in what the problem was so please do keep us updated.

 

[Myfordman]

Rest assured that if I am involved with the repair, I will write up the details.
Speed control on single phase induction motors gets asked about from time to time and the knowledge I hope to gain from this will almost certainly lead to an extra section in my induction motor paper. The paper has been based on many of the questions I get asked about induction motors over the years, hopefully written is a fairly digestible form. The current version can be accessed via the link the footer of my posts.

 

[Jaco]

Hegner UK are extremely expensive!

 

[raythompson102]

I have owned a Hegner for over 20 years and have done a couple of videos on their use etc. the only thing that went wrong with mine so far is that cheaply made little on off switch which Hegner wanted to charge £24 for but which is a bog standard switch widely available for around £1.


Now I have spent most of my working life with electric motors and machinery but the problem is that Hegners use Induction motors , which is good because they are very reliable and only very rarely give any problems.

The problem with induction motors is with speed control, it's not straightforward, most machines with variable speed controllers use the series wound/carbon brush type motor which can be built in when the device is manufactured or can be added later with hardly any problems. You can't do this with induction motors and those motors such as Hegner use are special and to be honest I know very little about the way they are controlled.

Normal (single phase) induction motors and series wound motors have mostly just have two wires supplying current to them (+Earth) but these special motors have more wires and their speed control is quite complicated which I know little about because my Hegner is the only machine/appliance that I have come across with a speed controlled induction motor.

In 40+working with motors years the only ones that I have experienced with speed control have been universal or carbon brush type motors which can easily be controlled with simple electronics such as thyristor or triac control. The Hegner speed control is quite different and I have practically zero knowledge of how it all works.

The price Hegner charges for a new motor is quite ridiculous but I would doubt that your motor itself is faulty more likely something external to it such as the capacitor/wiring or controller. There is some information on the net about single phase induction motor speed control but it is mostly very technical.

As I say I would be very surprised if the actual motor itself is faulty, they are very reliable and during 1000's of motor faults I have been involved with only about 3 or 4 induction motors had burnt out or faulty windings and they were due to external faults such as a seized gearbox etc.

If you do sort it out I would be interested in what the problem was so please do keep us updated.

Hi Scrimper, an earlier conversation someone said I should contact you as you are very pro Hegner and are /or used to be in the electrical feed, thank you for comments. I am a subscriber to to your u tube channel. I also follow Dai (love) spoons who also has 2 Hegner and really rates them. It was him that said his had to have a new capacitor for his machines over the last 20 years, however his machines are only single speed not variable speed like mine. I’ve contacted Hegner UK and requested prices for a new PCB and also for a new variable speed foot pedal which they have recently brought out which can be retrofitted to an existing variable speed model. Obviously I’ll have to wait till they’re back at work tomorrow.

 

[raythompson102]

Hegner UK are extremely expensive!

You’re not kidding. They are good quality saws, very well made but the design is somewhat dated nowadays compared with the newer models. I think it is a bit of the “emperors new clothes syndrome”. I also have an Axminster (trade) AT535SS scroll saw with a tilting head rather than the table and much prefer that, also the top arm lifts up so you can feed the blade from the top rather than underneath, which I find easier and the blade clamps are attached to the ends of the arms and are tightened just with them screws.
I am looking forward to trying the Hegner though just to see what all the fuss is about. Once I can get it working.

 

[raythompson102]

Thank you for that generous offer Ray.
alternatively if their price is high, I might be able to sort yours out if you send me the motor and controller. Having done a bit of research I’m feeling pretty confident that I will be able to analyse the problem. About the only part that might be less easy to source is the tachometer device should that turn out to be faulty.
Let me know what you decide when you get the pcb price.

Thanks for the offer, I’ll keep you posted. I should hopefully get the prices some time this week.

 

[raythompson102]

I’ve finally had a reply from Hegner UK Ltd. They sent me a connection diagram for the PCB, which I already had as I had photographed it when I first disassembled it, however I didn’t know the connections for the two tacho sensor wires so that was useful.
they also gave me a price for a new speed controller complete which is an eye watering £187.00. So according to Hegner the only row choices I have is a new motor or a new speed controller.
because the sensor wires were too short I have extended them so they are pulled when the top is removed. I’ve now reassembled everything and gave it one last try.

It is indeed the ic you mention, the U211B and looking at the data sheet I think diagrammed no.10 is probably the circuit diagrammed of my controller. I’ve asked Hegner for a price for a new PCB so I’ll wait and see what they come up with. If I can get a new one, you are welcome to have the old one to play with.

if you could have a look at it for me I be very grateful?

 

[raythompson102]

Thanks for the offer, I’ll keep you posted. I should hopefully get the prices some time this week.

I’ve had a quote for a new speed controller for £187.00 so would like you to have a look at it for me please?

 

[Myfordman]

PM sent Ray.

 

[Bungalowbill63]

Wow! That’s expensive,is it worth it?
Your options are limited here to
1 a Hegner repair, done by them with a guarantee.
2 have it repaired by someone who is an “expert” but never seen one before,
3 sell it for spares and put the money you would have spent on a working Machine.
4 stick with the saw you already have.

 

[raythompson102]

I agree, it is expensive. Hegner UK I think are only distributors and don’t have a repair service. They haven’t offered such a service. Someone on the forum has offered to repair it for me, so that is the way I am going. I’ve seen a similar one on ebay, in working order for approx £450 so even if I have to buy the new controller it would still be worthwhile.

 

[scrimper]

I agree, it is expensive. Hegner UK I think are only distributors and don’t have a repair service. They haven’t offered such a service. Someone on the forum has offered to repair it for me, so that is the way I am going. I’ve seen a similar one on ebay, in working order for approx £450 so even if I have to buy the new controller it would still be worthwhile.

The price they are charging for that speed control module is utterly ridiculous and the only way they can get away with such a ludicrous high price is because it is bespoke to them and there is no alternative. The problem is that Hegner saws don't sell in the huge quantities like electrical appliances do and therefore no third party company will tool up to offer a cheaper pattern part given the few they would sell.

Having said the above if you are sure that buying a new speed control will solve the problem and you end up with a good fully working machine. I say it would be worth spending the cash but I would resent paying the money out!

Hegner saws though expensive to purchase are superb machines and are normally very reliable, they are a joy to use, so quiet running and vibration free. I use mine a lot not just for fretwork but for other workshop tasks, compared to a noisy 'ferocious' bandsaw they are enjoyable to use.

You would not be able to buy a new quality Scrollsaw for the money asked for that control unit and once you have the saw working properly you will soon forget the money you spent. On the other hand buy a cheap machine and you will regret it every time you use it.

 

[Myfordman]

I now have the motor and controller from Ray. Not much free time at the moment but I can confirm that the motor is fine and that the tacho generator appears to to be working producing 550mv ac at 1425 rpm.
The controller has two possibly three obsolete components in it one of which is unique but too early to tell if this will be a problem.
Hegner have either bought a lifetime supply of the controller chip from Atmel before it went extinct or will have had to stand the cost of developing a whole new speed controller module which will have set them back £10s of thousands as a minimum.

 

[Spectric]

Sounds like this Hegner controler needs reverse engineering, not difficult unless it uses programable devices such as an ASIC or microcontroller. With modern microcontrollers and power devices from people like microchip it should not be a massive undertaking to overcome, just that the market seems small. Even the development tools from Microchip are a free download to produce and compile the required code, biggest issues now are that components are surface mount and not through hole which can make even prototyping more difficult.

"bought a lifetime supply of the controller chip from Atmel before it went extinct " Looking at that PCB it looks like Hegner have not changed that design for a long time, at some point they must run into component obsolescence issues so you would have thought they would be making sure they have something in the pipeline for when this happens.

Be interesting to know more how Hegners control method works, as

but these special motors have more wires

 

[Myfordman]

The motors are bog standard permanent split phase types. The only deviation from normal is a small tacho generator tucked in behind a slimmer than normal cooling fan.

The integrated circuit is an analogue chip designed for phase control of a triac with feedback from the tacho. The sort of thing that used to be used in washing machines but these days they use direct drive 3 phase motors. I suspect the market has just gone for this sort of device.

The obvious way ahead for Hegner or repairs would appear to be a small 3 phase motor and a modular vector inverter. The motor is only 100watts. This should cost a bit less than a replacement Hegner controller.

 

[raythompson102]

The price they are charging for that speed control module is utterly ridiculous and the only way they can get away with such a ludicrous high price is because it is bespoke to them and there is no alternative. The problem is that Hegner saws don't sell in the huge quantities like electrical appliances do and therefore no third party company will tool up to offer a cheaper pattern part given the few they would sell.

Having said the above if you are sure that buying a new speed control will solve the problem and you end up with a good fully working machine. I say it would be worth spending the cash but I would resent paying the money out!

Hegner saws though expensive to purchase are superb machines and are normally very reliable, they are a joy to use, so quiet running and vibration free. I use mine a lot not just for fretwork but for other workshop tasks, compared to a noisy 'ferocious' bandsaw they are enjoyable to use.

You would not be able to buy a new quality Scrollsaw for the money asked for that control unit and once you have the saw working properly you will soon forget the money you spent. On the other hand buy a cheap machine and you will regret it every time you use it.

Hi, I’ve had a number of scroll saw over the years, starting with a cheap one and upgrading to the one I now have. I do however want to try the Hegner to see what all the fuss is about. I can then decide which one to keep. I do agree though that you tend to get what you pay for.

 

[Bungalowbill63]

Rolls Royce prices for Ford parts and no repair service,Hegner really do need to up their game.
They mainly sell to the schools and colleges but rip them off as well,I don’t expect they care about individual sales or service.
A poor show from one of the so called market leaders.
I hope you get it fixed Ray,

 

[scrimper]

When I bought my Hegner back in 1999 the company then HegnerUK was run by a very approachable man called Roger Buse but I understand he retired 12 years ago and the company was taken over by TSL.
Roger was always very knowledgeable about the machines and scroll-sawing in general and always happy to give helpful advice.

I can't comment on the service offered by the new company as I have not had any reason to contact them.

 

[raythompson102]

When I bought my Hegner back in 1999 the company then HegnerUK was run by a very approachable man called Roger Buse but I understand he retired 12 years ago and the company was taken over by TSL.
Roger was always very knowledgeable about the machines and scroll-sawing in general and always happy to give helpful advice.

I can't comment on the service offered by the new company as I have not had any reason to contact them.

Hegner UK is now run by W F Education Group. They are helpful but I feel not as knowledgeable with regards the machines. They didn’t offer a repair service and told me the prices for spare parts are determined by Hegner gmbh. The speed controller spare part is not in stock in the UK and would have to be ordered from Germany