Waeco inverters, tool transformers?

[Timleech]

I need an inverter mainly to run power tools, it'll eventually be installed in a workboat but have an urgent need for one as a portable item.

I see Midland Chandlers are offering the Waeco 2kW modified sine for about the same money as Sterling's slightly smaller item.

Anyone any experience of these?

Also what are the chances of running 110V tools via a transformer from one, are they likely to cope with the inrush current of a '2kW' tool transformer?

 

Thanks

Tim

[Gibbo]

I need an inverter mainly to run power tools, it'll eventually be installed in a workboat but have an urgent need for one as a portable item.

I see Midland Chandlers are offering the Waeco 2kW modified sine for about the same money as Sterling's slightly smaller item.

Anyone any experience of these?

Also what are the chances of running 110V tools via a transformer from one, are they likely to cope with the inrush current of a '2kW' tool transformer?

 

Thanks

Tim

 

You might have a bit of a problem here.

 

Power tools are one of the nastiest loads around for MSW inverters. They're not too bad on pure sine because of the differences between the protection in the two types of inverter.

 

When I used to repair inverters we reckoned that about 50% of those with extensive damage were running a power tool at the time of failure. Usually the instant the trigger was pressed.

 

It is true that many people do successfully run power tools from MSW inverters but the odd one who says "my grinder is fine on my inverter" isn't statistically valid when placed alongside the several thousand that my company repaired. We were the sole UK approved repair centre for the (at the time) largest inverter manufacturer in the world so what we saw was a true representation of the failures as we saw all of them.

 

I find it interesting that of the remaining 50% only about 1 in 25 were due to a latent manufacturing faults, design faults or random component failures. All the rest were due to user abuse such as reverse battery polarity, AC backfeed or water damage.

 

You might also want to consider using a 110 Volt inverter instead of a transformer on a 230 Volt one. 110 Volt are more reliable (technical reasons for this).

 

Gibbo

[Greybeard]

You might have a bit of a problem here.

 

Power tools are one of the nastiest loads around for MSW inverters. They're not too bad on pure sine because of the differences between the protection in the two types of inverter.

 

When I used to repair inverters we reckoned that about 50% of those with extensive damage were running a power tool at the time of failure. Usually the instant the trigger was pressed.

 

It is true that many people do successfully run power tools from MSW inverters but the odd one who says "my grinder is fine on my inverter" isn't statistically valid when placed alongside the several thousand that my company repaired. We were the sole UK approved repair centre for the (at the time) largest inverter manufacturer in the world so what we saw was a true representation of the failures as we saw all of them.

 

I find it interesting that of the remaining 50% only about 1 in 25 were due to a latent manufacturing faults, design faults or random component failures. All the rest were due to user abuse such as reverse battery polarity, AC backfeed or water damage.

 

You might also want to consider using a 110 Volt inverter instead of a transformer on a 230 Volt one. 110 Volt are more reliable (technical reasons for this).

 

Gibbo

 

That's interesting and just saved me a few quid as I was about to put a 110v transformer onto the inverter 230v so thanks for that.

 

As a slight aside have you come accross anything else that would cause the same damage to an inverter ie a hoover or microwave for instance or is it just the industrial rated tools like grinders etc ?

[Gibbo]

That's interesting and just saved me a few quid as I was about to put a 110v transformer onto the inverter 230v so thanks for that.

 

As a slight aside have you come accross anything else that would cause the same damage to an inverter ie a hoover or microwave for instance or is it just the industrial rated tools like grinders etc ?

 

Big stuff that's near the limit of the inverter. Say a 650 Watt drill or grinder on an 800 Watt inverter. Though I've even known similar sized equipment blow up 1500 and 1800 Watt inverters. The start up surge *causes* the problem though it's a bit of a long winded knock on effect that finally blows them.

 

Never been aware of a problem with domestic stuff like vacuums. Just power tools. Especially the vari speed ones. Never worked out why the difference.

 

Gibbo

[larkshall]

Big stuff that's near the limit of the inverter. Say a 650 Watt drill or grinder on an 800 Watt inverter. Though I've even known similar sized equipment blow up 1500 and 1800 Watt inverters. The start up surge *causes* the problem though it's a bit of a long winded knock on effect that finally blows them.

 

Never been aware of a problem with domestic stuff like vacuums. Just power tools. Especially the vari speed ones. Never worked out why the difference.

 

Gibbo

 

 

GIbbo, would this also apply to variable speed vacuum cleaners (eg Panasonic), just a thought having blown up a 1kw inverter while back?, swapped to using a smallish motor generator

[Gibbo]

GIbbo, would this also apply to variable speed vacuum cleaners (eg Panasonic), just a thought having blown up a 1kw inverter while back?, swapped to using a smallish motor generator

 

I honestly don't know. I'm pretty sure it isn't the variable speed that's the actual problem. I think it's the type of motor.

 

What happens with power tools is that the surge (inrush) current is enormous when starting up the motor. I hear figures of 2 to 3 times the running current. This is rubbish. We regularly measured start up currents of 7 to 10 times the running current.

 

The inverter tries to power this then the inverter protection kicks in due to excess current. When this happens it switches off the output transistors and the main voltage upconverter. The motor now produces a huge back EMF into the output of the inverter which zaps the output transistors. There's nothing the inverter can do about it.

 

Pull the mains plug out with an electric drill running and touch the pins. No DON'T! That's what the inverter has to deal with.

 

Power tool motors seem to be far nastier in this regard than those used in vacuum cleaners etc even though on the face of it they appear to be the same type.

 

Gibbo

[Timleech]

You might have a bit of a problem here.

 

Power tools are one of the nastiest loads around for MSW inverters. They're not too bad on pure sine because of the differences between the protection in the two types of inverter.

 

When I used to repair inverters we reckoned that about 50% of those with extensive damage were running a power tool at the time of failure. Usually the instant the trigger was pressed.

 

It is true that many people do successfully run power tools from MSW inverters but the odd one who says "my grinder is fine on my inverter" isn't statistically valid when placed alongside the several thousand that my company repaired. We were the sole UK approved repair centre for the (at the time) largest inverter manufacturer in the world so what we saw was a true representation of the failures as we saw all of them.

 

I find it interesting that of the remaining 50% only about 1 in 25 were due to a latent manufacturing faults, design faults or random component failures. All the rest were due to user abuse such as reverse battery polarity, AC backfeed or water damage.

 

You might also want to consider using a 110 Volt inverter instead of a transformer on a 230 Volt one. 110 Volt are more reliable (technical reasons for this).

 

Gibbo

 

Thanks for that.

Where in the UK might I find a 12V to 110V inverter at a price comparable to the 240V equivalent?

The obvious snag with that route is that it's limited to running 110V equipment.

Re the 240/110 transformer, how would the bog standard MSW inverter react to that?

 

Tim

[Gibbo]

Thanks for that.

Where in the UK might I find a 12V to 110V inverter at a price comparable to the 240V equivalent?

The obvious snag with that route is that it's limited to running 110V equipment.

Re the 240/110 transformer, how would the bog standard MSW inverter react to that?

 

Tim

 

ebay is full to the brim of 110 volt ones.

 

Inverters are fine with transformers. Until they get overloaded and try to protect themselves. Then you get the same problem as with power tools.

 

I'm not saying power tools *always* blow inverters up. Just that power tools account for about half of the several thousand (possibly tens of thousands) failures we repaired.

 

Gibbo

[Greybeard]

ebay is full to the brim of 110 volt ones.

 

Inverters are fine with transformers. Until they get overloaded and try to protect themselves. Then you get the same problem as with power tools.

 

I'm not saying power tools *always* blow inverters up. Just that power tools account for about half of the several thousand (possibly tens of thousands) failures we repaired.

 

Gibbo

 

Following on from your advice on power tools, the problem, for me at least, is battery capacity now.

 

I already have an 1800watt 230v inverter with a 440ah battery bank and I'm not sure if say a 1700watt 110v inverter would work as well.

 

Would it be feasible to put a switch in place to charge one or the other?

 

Mike

[Gibbo]

Following on from your advice on power tools, the problem, for me at least, is battery capacity now.

 

I already have an 1800watt 230v inverter with a 440ah battery bank and I'm not sure if say a 1700watt 110v inverter would work as well.

 

Would it be feasible to put a switch in place to charge one or the other?

 

Mike

 

I don't even understand the question!

 

A 1700 Watt inverter is a 1700 Watt inverter. It makes no difference what the output voltage is. It will still use 1700 Watts form the inverter at full power.

 

Are you thinking both might be used at the same time on full power and you want to avoid that?

 

Gibbo

[Timleech]

ebay is full to the brim of 110 volt ones.

 

Inverters are fine with transformers. Until they get overloaded and try to protect themselves. Then you get the same problem as with power tools.

 

Gibbo

 

I can't see any on ebay UK at the moment.

 

I have a 3.5kVA tool transformer which occasionally blows the 13A plug fuse on being switched on (with no load), while I wouldn't try that one with a 2 kW inverter it made me wonder about the effect of transfomers on inverters.

 

Tim

[smileypete]

I can't see any on ebay UK at the moment.

 

I have a 3.5kVA tool transformer which occasionally blows the 13A plug fuse on being switched on (with no load), while I wouldn't try that one with a 2 kW inverter it made me wonder about the effect of transfomers on inverters.

 

Tim

 

Hi,

 

Try looking for 'site transformer'

 

 

One way to overcome the inrush problem is with one or more inrush limiters:

 

http://www.rapidonline.com/Electronic-Comp...-limiters/31809

 

Note they get very hot in use so need careful mounting and ventilation.

 

Better still combine them with an 'active RCD' that needs a reset if the power fails momentarily.

 

cheers,

Pete.

[Timleech]

Hi,

 

Try looking for 'site transformer'

 

 

 

cheers,

Pete.

 

 

 

Try reading the thread?

 

Tim

[smileypete]

Try reading the thread?

 

I just skimmed the thread and assumed you were looking for a smaller site transformer, a 1kVA or 500VA might start OK off a 2kW inverter.

 

The short answer is that you can't run a 2kVA site transformer off a 2kW MSW inverter.

 

(But I can )

 

cheers,

Pete.

Edited June 21, 2008 by smileypete

[Greybeard]

I don't even understand the question!

 

A 1700 Watt inverter is a 1700 Watt inverter. It makes no difference what the output voltage is. It will still use 1700 Watts form the inverter at full power.

 

Are you thinking both might be used at the same time on full power and you want to avoid that?

 

Gibbo

 

Badly worded question.

 

What I meant was I don't think my batteries would charge both inverters at the same time and would it be feasible to switch the batteries from charging one inverter to the other.

 

The answer I would guess would be yes.

 

I'll drink less lager before putting any further questions on.

 

Soz for confusion!

[DHutch]

If you run the 1800watt and 1700watt at the same time, then the total load will be around twice that of either of them running on there own. Assuming they are approximately equally loaded. And if loaded to there rated maximum 3.5kilowatts in total, which around 300-350 amps draw from the batteries, which is a hell of a lot to ask for anything other than an instantaneous load without having a lot of batteries!

[Greybeard]

If you run the 1800watt and 1700watt at the same time, then the total load will be around twice that of either of them running on there own. Assuming they are approximately equally loaded. And if loaded to there rated maximum 3.5kilowatts in total, which around 300-350 amps draw from the batteries, which is a hell of a lot to ask for anything other than an instantaneous load without having a lot of batteries!

 

That's why I'm looking to charge one of them at a time.

 

This is how I managed to confuse things in the first place.

 

Think I'll buy cordless and charge them at home!!!!!!!!!

 

Thanks anyway.

[DHutch]

Well you certainly could put in place a switch in the supply preventing both of them being used together. Or just use some self restrain.

- Tbh however, if you did try they would proberbly very quickly pull the supply voltage down to below the cut off threshhold of 10volts or whatever they usally knock themselfs off at.

 

Also as a point of interest, you dont charge inverters as such. You supply they with electricity, with the batterys. Batterys can be charged, but not inverters.

[Greybeard]

Well you certainly could put in place a switch in the supply preventing both of them being used together. Or just use some self restrain.

- Tbh however, if you did try they would proberbly very quickly pull the supply voltage down to below the cut off threshhold of 10volts or whatever they usally knock themselfs off at.

 

Also as a point of interest, you dont charge inverters as such. You supply they with electricity, with the batterys. Batterys can be charged, but not inverters.

 

I am using maximum self restrain at this moment in time!

 

Point taken.

[DHutch]

I have to say i am interested in this too.

- We currently carry a 1kw petrol genny on board, which is a bit of a hassle and pain, and gets used very little bar when we're doing work on her. When we could easly bring it down in the car if needed.

 

However. There is times when you do absoulatly just really need some mains! Just for that one minute just to do somthing or fix somthing.

- We have a pretty powerfull cordless as well, which can do most small things (its a cheapish one, but does very few hours) too. But it would be very handy to be able to run a 750watt drill or angle grinder for a minute or two time-to-time without carrying the generator. Ie, have an inveter. But as always its never that simple. And there not cheap!

 

Also a small (300w ish) inverter would be nice for charging odd laptops and guests non-nokia mobile phones off. And charging the cordless even!

 

 

Daniel

[Greybeard]

After Gibbos timely advice on tooling transformers I've been looking elsewhere at alternatives for power tools.

 

I've come up with the following so far & like Dhutch says it's handy just to have a drill etc for a couple of minutes sometimes.

 

http://www.chronos.ltd.uk/acatalog/copy_of...xxon_Tools.html

 

or

 

http://www.tool-shop.co.uk/acatalog/12v_Handheld_Tools.html

 

I know they're not going to drill holes through 1" steel plate but just for light work they may be useful depending on whether the transformer or mains adaptor would damage the inverter. Far beyond my knowledge.

 

There's probably all kinds of tools out there but the above is what I've found so far.

[smileypete]

However. There is times when you do absoulatly just really need some mains! Just for that one minute just to do somthing or fix somthing.

- We have a pretty powerfull cordless as well, which can do most small things (its a cheapish one, but does very few hours) too. But it would be very handy to be able to run a 750watt drill or angle grinder for a minute or two time-to-time without carrying the generator. Ie, have an inveter. But as always its never that simple. And there not cheap!

 

A lot of these tools have 'universal motors' that will run off DC.

 

So if you have 110V tools and 8 or 9 12V batteries, you're all set!

 

6 batteries might do...

 

 

Edit:

 

My grinder works passably well off half voltage, cuts through M6 bolts no problem using 200W in doing so.

 

So running a 110V grinder off a couple of 24V battery packs or three 18V packs might be fine for some short jobs.

 

cheers,

Pete.

Edited June 22, 2008 by smileypete