Help with inrush current!

[paddy mcbride]

Hi guys,

I've tried to come up with a solution but would like some advice. I am sure there is someone on here that can help.

I have an Ampeg SVT6 Pro and on start up at the rehearsal room it trips the MCB. When management reset the MCB and i power up it doesn't trip again.

I love my amp and didn't have any issues like this in the shop or my house. I have even started powering up my amp before anything else is turned on.....we even turn off the lights.

Can someone suggest a way of preventing this amp from tripping the power? The management are getting pissed off and I am now concerned about using the amp at venues.


Any help will be appreciated.


Thank you


Paddy

[martinbass7750]

Hi Paddy,

Your problem could be high earth leakage - worth getting it checked by an electrician.

Or it could just be that on switch on there is a surge which takes the trip out.

This can usually be resolved by adding a device to limit the inrush, but it has to be in series with the mains Line connection.

Here is a component that will achieve what you want,

[url="http://www.rhopointcomponents.com/products.asp?recnumber=10"]http://www.rhopointcomponents.com/products.asp?recnumber=10[/url]

but you need to know what you are doing to add it safely. The best way is to have it connected inside your amp in the mains input connection. You also need to choose the correct device to match the running current of your amp.

Not sure if you can buy a mains adapter with a SurgeGuard in, but it would be worth searching around on the net.

The device is basically a resistor which has a high resistance when cold (which limits the inrush current) but as it warms up after switch on its resistance drops to allow the normal running current to flow.

Hope that helps a bit.

Cheers

Martin

Edited December 9, 2008 by martinbass7750

[paddy mcbride]

Thank you.

I don not have experience with electronics so won't be able to install that myself.

Would a power conditioner help? I know that it only has a 10A breaker. That would trip and i could reset it.....then on powering up again it won't trip the second time. Am i right? I am nervous to have any mods done to the circuitry of the amp unless it is definitely the best solution.





[quote name='martinbass7750' post='349345' date='Dec 9 2008, 08:26 AM']Hi Paddy,

Your problem could be high earth leakage - worth getting it checked by an electrician.

Or it could just be that on switch on there is a surge which takes the trip out.

This can usually be resolved by adding a device to limit the inrush, but it has to be in series with the mains Line connection.

Here is a component that will achieve what you want,

[url="http://www.rhopointcomponents.com/products.asp?recnumber=10"]http://www.rhopointcomponents.com/products.asp?recnumber=10[/url]

but you need to know what you are doing to add it safely. The best way is to have it connected inside your amp in the mains input connection. You also need to choose the correct device to match the running current of your amp.

Not sure if you can buy a mains adapter with a SurgeGuard in, but it would be worth searching around on the net.

The device is basically a resistor which has a high resistance when cold (which limits the inrush current) but as it warms up after switch on its resistance drops to allow the normal running current to flow.

Hope that helps a bit.

Cheers

Martin[/quote]

[martinbass7750]

Hi Paddy,

A power conditioner is designed to stop surges in the mains from damaging your kit, I don't believe they will do what you want.

I've just done a quick search and come up with this - this should do the trick for you.

[url="http://www.canford.co.uk/ProductResources/ig/1916.pdf"]http://www.canford.co.uk/ProductResources/ig/1916.pdf[/url]

It's probably the surge guard component in a nice box!

Cheers

Martin


[quote name='paddy mcbride' post='349358' date='Dec 9 2008, 08:52 AM']Thank you.

I don not have experience with electronics so won't be able to install that myself.

Would a power conditioner help? I know that it only has a 10A breaker. That would trip and i could reset it.....then on powering up again it won't trip the second time. Am i right? I am nervous to have any mods done to the circuitry of the amp unless it is definitely the best solution.[/quote]

[bremen]

[quote name='martinbass7750' post='349345' date='Dec 9 2008, 08:26 AM']Here is a component that will achieve what you want,

[url="http://www.rhopointcomponents.com/products.asp?recnumber=10"]http://www.rhopointcomponents.com/products.asp?recnumber=10[/url]

but you need to know what you are doing to add it safely. The best way is to have it connected inside your amp in the mains input connection. You also need to choose the correct device to match the running current of your amp.

Not sure if you can buy a mains adapter with a SurgeGuard in, but it would be worth searching around on the net.

The device is basically a resistor which has a high resistance when cold (which limits the inrush current) but as it warms up after switch on its resistance drops to allow the normal running current to flow.[/quote]

I use these in my amps.

It shouldn't be difficult to make an inline unit in an ABS box with an IEC lead on the output and a mains lead on the input. If anyone's interested I can specify the parts from Maplin or similar and draw a schematic of how to wire it all up.

edit: or buy the one Martin found :-)

Edited December 9, 2008 by bremen

[martinbass7750]

[quote name='bremen' post='349420' date='Dec 9 2008, 09:44 AM']I use these in my amps.

It shouldn't be difficult to make an inline unit in an ABS box with an IEC lead on the output and a mains lead on the input. If anyone's interested I can specify the parts from Maplin or similar and draw a schematic of how to wire it all up.

edit: or buy the one Martin found :-)[/quote]


The one I found is quite expensive, personally I'd go for the surge guard route (I've used them successfully in similar applications before)

I don't think Maplin sell surge guards any more.

I reckon there's a market here for a surge guard in a box with an IEC in and out.

Cheers

Martin

[bremen]

[quote name='martinbass7750' post='349428' date='Dec 9 2008, 09:54 AM']The one I found is quite expensive, personally I'd go for the surge guard route (I've used them successfully in similar applications before)

I don't think Maplin sell surge guards any more.

I reckon there's a market here for a surge guard in a box with an IEC in and out.

Cheers

Martin[/quote]

Farnell do them:

[url="http://uk.farnell.com/rhopoint/sg110/thermistor-ntc-surge-gard/dp/1186611"]http://uk.farnell.com/rhopoint/sg110/therm...gard/dp/1186611[/url]

[mybass]

[quote name='paddy mcbride' post='349328' date='Dec 9 2008, 07:46 AM']Hi guys,

I've tried to come up with a solution but would like some advice. I am sure there is someone on here that can help.

I have an Ampeg SVT6 Pro and on start up at the rehearsal room it trips the MCB. When management reset the MCB and i power up it doesn't trip again.

I love my amp and didn't have any issues like this in the shop or my house. I have even started powering up my amp before anything else is turned on.....we even turn off the lights.

Can someone suggest a way of preventing this amp from tripping the power? The management are getting pissed off and I am now concerned about using the amp at venues.


Any help will be appreciated.

Could the problem be in the rehearsal studio wiring? Maybe something there needs double checking seeing as you don't have problems in other buildings. Do any other amps do that to their trips and does it happen in one room only or in other rehearsal rooms?

Thank you


Paddy[/quote]

[paddy mcbride]

Thanks for the info so far. The canford mains inrush protector looks like what i want but i don't wanna spend £70+ on one.

I have purchased the thermistor . bremen Can you please send me a schematic for wiring this?

Thanks again

[martinbass7750]

[quote name='bremen' post='349436' date='Dec 9 2008, 10:03 AM']Farnell do them:

[url="http://uk.farnell.com/rhopoint/sg110/thermistor-ntc-surge-gard/dp/1186611"]http://uk.farnell.com/rhopoint/sg110/therm...gard/dp/1186611[/url][/quote]


indeed they do (as do R-S) but I'm not sure they will supply unless you have an account.

CPC probably will supply though (part of Farnell, but more for the general public)

[bremen]

[quote name='martinbass7750' post='349538' date='Dec 9 2008, 11:28 AM']indeed they do (as do R-S) but I'm not sure they will supply unless you have an account.

CPC probably will supply though (part of Farnell, but more for the general public)[/quote]

Farnell used to sell only to account customers, but they now do credit card transactions for messrs Tom, Dick and Harry.

[bremen]

[quote name='paddy mcbride' post='349470' date='Dec 9 2008, 10:51 AM']Thanks for the info so far. The canford mains inrush protector looks like what i want but i don't wanna spend £70+ on one.

I have purchased the thermistor . bremen Can you please send me a schematic for wiring this?

Thanks again[/quote]

Ok, I'll get onto this soonas the boss looks away...

[bremen]

[quote name='bremen' post='349557' date='Dec 9 2008, 11:43 AM']Ok, I'll get onto this soonas the boss looks away...[/quote]

here you go.

Remember the surge-gard gets hot, so keep it away from the insulation and case. The terminal block should probably be rated at 15A.

[paddy mcbride]

Easy when you how lol.

I'll try and fit it on sunday before rehearsal. Thanks again. Will post again to let you know how it goes.

Cheers

[paddy mcbride]

Bemen,

How hot can i expect this thermistor to get?

I have an idea to place the thermistor in an external box or single gang extension plug rather than opening up the amp.

[bremen]

[quote name='paddy mcbride' post='349649' date='Dec 9 2008, 01:03 PM']Bemen,

How hot can i expect this thermistor to get?

I have an idea to place the thermistor in an external box or single gang extension plug rather than opening up the amp.[/quote]

Too hot to touch, however hot that is!

[martinbass7750]

[quote name='bremen' post='349656' date='Dec 9 2008, 01:08 PM']Too hot to touch, however hot that is![/quote]


If you read the application note on the website I pointed to earlier, it recommends you use high temperature solder and keep the device well away from plastic components.

So I wouldn't mount it inside a plastic extension lead, if that's what you have in mind.

[paddy mcbride]

ok thanks for that

I have bought a single gang bow to house it in. it will have space and nothing will touch it. I chose the plastic over a metal one because of fears that i could make the metal box live if something got lose.


I will let you know if it works.




[quote name='martinbass7750' post='349716' date='Dec 9 2008, 01:54 PM']If you read the application note on the website I pointed to earlier, it recommends you use high temperature solder and keep the device well away from plastic components.

So I wouldn't mount it inside a plastic extension lead, if that's what you have in mind.[/quote]

[paddy mcbride]

Well guys it worked.


I bought an IP rated junction box and 2No. compression IP rated glands (so no beer or whatever can enter the box), a 15A terminal block and a single gang extension lead. I cut the lead quite near the socket end and joined it together again with the terminal block and thermistor in place as shown on the diagram [b]bremen[/b] gave us all enclosed within the IP rated box. It worked a treat. Simple, relatively cheap and hopefully will continue to work over time.....i can't see why not.

Thanks for all your input.

Cheers

Paddy

[martinbass7750]

[quote name='paddy mcbride' post='354832' date='Dec 15 2008, 10:14 AM']Well guys it worked.


I bought an IP rated junction box and 2No. compression IP rated glands (so no beer or whatever can enter the box), a 15A terminal block and a single gang extension lead. I cut the lead quite near the socket end and joined it together again with the terminal block and thermistor in place as shown on the diagram [b]bremen[/b] gave us all enclosed within the IP rated box. It worked a treat. Simple, relatively cheap and hopefully will continue to work over time.....i can't see why not.

Thanks for all your input.

Cheers

Paddy[/quote]


Glad it worked - we all knew it would really!