Exploding Mastervolt

[Chris Pink]

Followers of my rants will no doubt remember my critique of Mastervolt's after sales service following the death of my IVO-Smart 40-3 charger.

 

Anyway... a bit of exploratory surgery has revealed a rather sorry looking component, wired across the live and neutral mains input.

 

Any ideas what it might be? or what I can replace it with? or whether I can just run it without?

it smells like blown-up capacitor

 

There was 22Ω across the input before snipping this part, it's a (sort of) open circuit now, although there appears to be a capacitor charging which is reading 2µF

The fuse is intact, if a little cosmetically challenged after being sprayed with exploding component.

 

After teasing apart

as found

[Chalky]

I would suspect that it was a transient suppressor (Tranzorb). They have a high impedance at the normal operating voltage which drops as the voltage rises to their conductance point - a sort of super zener diode. If they're asked to supress more than they're designed for they tend to let go in a terminal way.

[Keeping Up]

I'd also vote for a transient suppressor - something like this perhaps?

[Chris Pink]

I would suspect that it was a transient suppressor (Tranzorb). They have a high impedance at the normal operating voltage which drops as the voltage rises to their conductance point - a sort of super zener diode. If they're asked to supress more than they're designed for they tend to let go in a terminal way.

 

so worth powering up without it to find out if that's the only thing wrong?

[pete.i]

I would suspect that it was a transient suppressor (Tranzorb). They have a high impedance at the normal operating voltage which drops as the voltage rises to their conductance point - a sort of super zener diode. If they're asked to supress more than they're designed for they tend to let go in a terminal way.

 

Yes Chalky is right. They used to be fitted to CRT televisions. Modern tellies probably have something similar but I haven't fixed tellies for a long while. Anyway my point is that they used to be a regular cause of problems. Usually when they blew they would take out the mains input fuse as well but in a lot of cases that component just blew for no apparent reason. Having said that Chalky is correct in that they can also blow if it cannot handle the transient.

 

Pete

[Chris Pink]

A search in google for "Transient Suppressor MOV' turns up the marque Littelfuse which is also marked on the PCB "Littlefuse Serie 215" so i think you have it chaps.

 

Thank you very much, I think I'll power up without before splashing out my 59p at Maplins.

[bizzard]

Looks like a bit of Black sausage to me.

[Keeping Up]

I've always distrusted Littelfuse products since I doscovered that they marketed a range of fuses which blew to a short-circuit condition when overloaded.

 

 

With a marked rating of 60mA, if you applied mains voltage across them they would of course blow; but if you then measured them you found that they conducted quite well and took nearly 200mA to blow again. This was because the wire was inside a very small ceramic tube, and when they blew the metal vappour would re-deposit itself on the inside of the tube as a conducting layer.

[Chalky]

A search in google for "Transient Suppressor MOV' turns up the marque Littelfuse which is also marked on the PCB "Littlefuse Serie 215" so i think you have it chaps.

 

Thank you very much, I think I'll power up without before splashing out my 59p at Maplins.

 

Have a look at Farnell. They sell a better range of suppressors than Maplins. It's common to find several of them connected in parallel to handle the power.

 

One of the ongoing "discussions" on the board has been about transients and the effect. A big transient will cause the suppression to fail suddenly as you've seen. A number of smaller ones don't kill the equipment straight away but they do weaken the components and cause the apparent random failures that pete.i described earlier.

[Taslim]

I would suspect that it was a transient suppressor (Tranzorb). They have a high impedance at the normal operating voltage which drops as the voltage rises to their conductance point - a sort of super zener diode. If they're asked to supress more than they're designed for they tend to let go in a terminal way.

 

That's right. probably something like an IE8. Chris, if you can't get one easily I can post you one. experience at work shows that they weaken over time and usualy go out with a bang.

 

taslim.

[Chris Pink]

This probably comes under the heading of 'masochism' or 'banging my head against a brick wall'

 

We'll assume this is an easily available part, costing a few pence and a reasonably easy soldering job (not a multi-layer board)

 

I emailed Mastervolt.

 

 

----Original Message-----

From: Chris Pink

Sent: 21 December 2011 10:51

To: Mastervolt UK

Subject: IVO-Smart 40-3

 

Hi

 

I have a small problem with my Mastervolt IVO-Smart 40-3. The transient

suppressor across the mains input has gone u/s (exploded to be precise) to

the point where it is not possible to get the part number from it.

 

Given that your policy with an item of this age is to mark it 'beyond

economic repair' I wonder if you would be so kind as to give me a part

number for the transorb so I might fix it myself. It is apparent that this

is the only thing wrong with the unit.

 

Many thanks, Chris

 

Hi Chris

 

I'm afraid we do not have access to this information as we do not repair units here in the UK. The unit can be sent to Holland for repair through ***, however if it is not cost effective to repair the unit you will get a dicount under the new for old policy.

 

Kind Regards

 

Oh, the good news is that once the debris was removed it's still apparently working ie it powers up ok. I've just got to replace the tranzorb.

Edited December 21, 2011 by Chris Pink

[smileypete]

I've always distrusted Littelfuse products since I doscovered that they marketed a range of fuses which blew to a short-circuit condition when overloaded.

 

 

With a marked rating of 60mA, if you applied mains voltage across them they would of course blow; but if you then measured them you found that they conducted quite well and took nearly 200mA to blow again. This was because the wire was inside a very small ceramic tube, and when they blew the metal vappour would re-deposit itself on the inside of the tube as a conducting layer.

What's their maximum interrupt rating, from the datasheet? Does this occur with fault currents below this rating?

 

cheers,

Pete.

Edited December 21, 2011 by smileypete

[Keeping Up]

What's their maximum interrupt rating, from the datasheet? Does this occur with fault currents below this rating?

 

cheers,

Pete.

 

Sorry, I've no idea (and it was 20 years ago so I can't remember).

 

The standard configuration that we were testing involved a fused input and a pair of back-to-back zeners clamping across the output. Our standard test was to apply raw 240v mains across the input and check that the fuse blew, then repeat 9 times more (ie 10 in all) and check that the clamp zeners were still working properly. Finally we applied 2800v from input to output and checked that there was no conductivity either through the fuses or across the printed circuit tracks. We didn't really care about the specifications, we just tested a sample number of units and required a 100% pass-rate before we would approve the equipment.

 

One big problem was that my boss at the time liked to take all his team out at lunchtime, and consume at least 5 pints. The lab tests used to get quite interesting, with us waving bare mains wires and 2800v probes around, in a fairly merry state - especially when the sound of the fuses blowing made you jump and apply 2800v to your colleague who was working at the next bench.

[Taslim]

Sorry, I've no idea (and it was 20 years ago so I can't remember).

 

The standard configuration that we were testing involved a fused input and a pair of back-to-back zeners clamping across the output. Our standard test was to apply raw 240v mains across the input and check that the fuse blew, then repeat 9 times more (ie 10 in all) and check that the clamp zeners were still working properly. Finally we applied 2800v from input to output and checked that there was no conductivity either through the fuses or across the printed circuit tracks. We didn't really care about the specifications, we just tested a sample number of units and required a 100% pass-rate before we would approve the equipment.

 

One big problem was that my boss at the time liked to take all his team out at lunchtime, and consume at least 5 pints. The lab tests used to get quite interesting, with us waving bare mains wires and 2800v probes around, in a fairly merry state - especially when the sound of the fuses blowing made you jump and apply 2800v to your colleague who was working at the next bench.

 

Ahh....Dear departed days.

 

These days one just goes to work, not to a real job. I blame it on the Elves & Fairy inspectors.

 

taslim.

[Proper Job]

This probably comes under the heading of 'masochism' or 'banging my head against a brick wall'

 

We'll assume this is an easily available part, costing a few pence and a reasonably easy soldering job (not a multi-layer board)

 

I emailed Mastervolt.

 

 

----Original Message-----

From: Chris Pink

Sent: 21 December 2011 10:51

To: Mastervolt UK

Subject: IVO-Smart 40-3

 

Hi

 

I have a small problem with my Mastervolt IVO-Smart 40-3. The transient

suppressor across the mains input has gone u/s (exploded to be precise) to

the point where it is not possible to get the part number from it.

 

Given that your policy with an item of this age is to mark it 'beyond

economic repair' I wonder if you would be so kind as to give me a part

number for the transorb so I might fix it myself. It is apparent that this

is the only thing wrong with the unit.

 

Many thanks, Chris

 

Hi Chris

 

I'm afraid we do not have access to this information as we do not repair units here in the UK. The unit can be sent to Holland for repair through ***, however if it is not cost effective to repair the unit you will get a dicount under the new for old policy.

 

Kind Regards

 

Oh, the good news is that once the debris was removed it's still apparently working ie it powers up ok. I've just got to replace the tranzorb.

You just know that it's not going to be cost effective to repair

 

Have you tried to get the contact details for the Dutch repair centre?

[GUMPY]

Oh, the good news is that once the debris was removed it's still apparently working ie it powers up ok. I've just got to replace the tranzorb.

The only thing that the MOV does is clamp high voltages that is its use in the circuit so the unit should work fine without it. What was powering the unit when it went bang? If it was a genset it would sugest that there are high voltage spikes coming from the set as the SMP in the mastervolt switches on and off, I have seen this many times, even on my own set. It is likely therefore that using the mastevolt on the same genset will weaken the mastervolt over a period of time due to the HV surges.

[Proper Job]

An interesting thread from a salty water forum:

 

link

[GUMPY]

An interesting thread from a salty water forum:

 

link

That is 6 years ago things may have improved

[Chris Pink]

The only thing that the MOV does is clamp high voltages that is its use in the circuit so the unit should work fine without it. What was powering the unit when it went bang? If it was a genset it would sugest that there are high voltage spikes coming from the set as the SMP in the mastervolt switches on and off, I have seen this many times, even on my own set. It is likely therefore that using the mastevolt on the same genset will weaken the mastervolt over a period of time due to the HV surges.

 

It was, I confess, my stupidity that blew this unit and the suppressor probably saved in by going short circuit.

 

I, um, fed it 400V when I should have checked first so at the moment I consider myself lucky if it still works.

 

What I now know about Mastervolt is that if money is no object their stuff is pretty good but nowhere near as good as their hype. If the usual reaction to a unit going u/s is 'replace it' and customer service non-existent then I expect this factored in the price.

 

I don't know what result would be to the same assessment of Victron as peers in price and build quality.

[smileypete]

If you want some cheap 'bulk' current for charging your US2200s why not make a simple transformer based 50A charger?

 

It could run alongside your existing switched mode one (the power factors will help to cancel each other )

 

cheers,

Pete.

[Chris Pink]

If you want some cheap 'bulk' current for charging your US2200s why not make a simple transformer based 50A charger?

 

It could run alongside your existing switched mode one (the power factors will help to cancel each other )

 

cheers,

Pete.

 

I do think there's a place for heavy metal in charging. It's got a bit of a bad press from those crappy 70s things. I used to have a big Sealey, £30 it cost and with the power factor the 'give it everything' jump start setting used to charge a treat.

[smileypete]

I do think there's a place for heavy metal in charging. It's got a bit of a bad press from those crappy 70s things. I used to have a big Sealey, £30 it cost and with the power factor the 'give it everything' jump start setting used to charge a treat.

One of these would be a good start, add an inrush limiter, ceramic terminal block, thermal cutout, two BIG diodes (for halfwave rectifier), some sort of voltage sensitive relay, maybe a basic shunt ammeter, 12V fan might be handy, gives you a reliable 40A bulk charger for £80ish? How much is a 40A Mastervolt these days?

 

cheers,

Pete

[Chalky]

One of these would be a good start, add an inrush limiter, ceramic terminal block, thermal cutout, two BIG diodes (for halfwave rectifier), some sort of voltage sensitive relay, maybe a basic shunt ammeter, 12V fan might be handy, gives you a reliable 40A bulk charger for £80ish? How much is a 40A Mastervolt these days?

 

cheers,

Pete

 

Toroids like the one you mention are expensive because they're difficult to wind. If you can get a transformer with a central bobin and core made of the traditional E & I laminations they should be cheaper since they're easier to wind. You'll also need a big heat sink for the diodes (as well as the usual mounting kits to keep them isolated).

[smileypete]

Toroids like the one you mention are expensive because they're difficult to wind. If you can get a transformer with a central bobin and core made of the traditional E & I laminations they should be cheaper since they're easier to wind. You'll also need a big heat sink for the diodes (as well as the usual mounting kits to keep them isolated).

Thesewill do for the diodes, one diode in each one for a half wave rectifier or the whole thing for full wave.

 

Also came across these15V 33A switching power supplies on Ebay that have current limiting.

 

 

It's a good sign when they post a pic of the innards too...

 

 

cheers,

Pete.