Soft Starter - one for the elecrical bods

[Midnight]

I have a 230v Jabsco waste pump with a full load current of 4.2 amps. My Mastervolt MASS inverter has a bit of trouble getting it started. Running the engine at high revs usually does the trick but I was wondering if I need to add one of those soft starter devices. Is that a good option? Replacing the inverter with a bigger model is going to be very expensive.

http://uk.rs-online.com/web/p/soft-starts/3305358/

[MtB]

That's an interesting and useful-looking piece of kit. 

Do buy one and let us know if it works, please!

[rusty69]

Dunno about the gizzmo, but are your batteries, cables, connectors in good condition. 

[MtB]

Just now, rusty69 said:

Dunno about the gizzmo, but are your batteries, cables, connectors in good condition. 

 

Poor condition cables and connectors on the output side would actually help the situation.

[Robbo]

If that doesn't work, look at the wiring between inverter and batteries, as well as battery health.   I'm guessing the inverter is trying to pull too many amps from the batteries and the voltage is dropping as the batteries can't supply it.    If batteries are healthy and charged, it's the type of battery or overall capacity that's an issue.

[Midnight]

2 minutes ago, rusty69 said:

Dunno about the gizzmo, but are your batteries, cables, connectors in good condition. 

Yes very good condition 2 x 240 ah batteries

[Robbo]

2 minutes ago, Midnight said:

Yes very good condition 2 x 240 ah batteries

Type and inverter kw?, also size and length of cables to the inverter?

In addition does the Inverter/Combi? have a separate voltage sensor for the batteries?

Edited June 29, 2017 by Robbo

[MtB]

6 minutes ago, Robbo said:

If that doesn't work, look at the wiring between inverter and batteries, as well as battery health.   I'm guessing the inverter is trying to pull too many amps from the batteries and the voltage is dropping as the batteries can't supply it.    If batteries are healthy and charged, it's the type of battery or overall capacity that's an issue.

 

No, from what the OP says, I think the inverter is objecting to the transient overload caused by the high start-up current of the hefty electric motor in his pump.

Bear in mind 4.2A and 240Vac is about a kW, and the transient start up current on this electric motor will be briefly attempting draw about about 40A, or 10kW. 

 

Edited June 29, 2017 by Mike the Boilerman

[Midnight]

3 minutes ago, Robbo said:

If that doesn't work, look at the wiring between inverter and batteries, as well as battery health.   I'm guessing the inverter is trying to pull too many amps from the batteries and the voltage is dropping as the batteries can't supply it.    If batteries are healthy and charged, it's the type of battery or overall capacity that's an issue.

Knowing very little about these things, I was wondering if that device would be likely to work or is it for some other use?
My system must be just borderline. The problem is worse when the batteries are not fully charged. If I run the engine at 2000 revs which boosts the battery charge voltage to around 14.2 volts it usually starts. Once started it runs just fine.

[Robbo]

1 minute ago, Mike the Boilerman said:

 

No, from what the OP says, I think the inverter is objecting to the transient overload caused by the high start-up current of the hefty electric motor in his pump. 

 

But works when the engine is running, so it's amp/voltage supply issue to the inverter.

[Robbo]

1 minute ago, Midnight said:

Knowing very little about these things, I was wondering if that device would be likely to work or is it for some other use?
My system must be just borderline. The problem is worse when the batteries are not fully charged. If I run the engine at 2000 revs which boosts the battery charge voltage to around 14.2 volts it usually starts. Once started it runs just fine.

The inverter is only struggling to get a supply for the inrush so yes it looks likely that will work.   (I would still look at the wiring if that is border line as well as many are installed undersized).

[Midnight]

31 minutes ago, Robbo said:

The inverter is only struggling to get a supply for the inrush so yes it looks likely that will work.   (I would still look at the wiring if that is border line as well as many are installed undersized).

Thanks I'll get one.

A couple more questions:

1/ do I just wire in into the socket which I use for the pump or into the pump itself?
2/ is it likely to do any damage to the pump motor over time?

[dmr]

Thats a very big pump, as said above 4amp is a kilowatt. What does it do and why do you need such a big pump?. Could you fit a whale gulper (12volt) instead? They work well and last forever.

............Dave

[Onewheeler]

It should work, my only reservation would be that it's not clear how it would like a modified square wave input. A PSW invertor should be OK. At 1 kW you'll need a heat sink, but not a big one.

 

Let us know how you get on! It might be a useful means of running a domestic macerator toilet from an invertor.

[Midnight]

1 hour ago, dmr said:

Thats a very big pump, as said above 4amp is a kilowatt. What does it do and why do you need such a big pump?. Could you fit a whale gulper (12volt) instead? They work well and last forever.

............Dave

I had a 12volt system (not the Whale which has 4 valves) for several years which was very unreliable and often left me covered in sh.... 'you know what' when the valves clogged up mid-pumpout - and had to be manually cleaned out - it also took 45 mins to pump the tank out. Not worth a light IMO.

The Jabsco 230v pump takes 50 seconds approx. to pumpout. doesn't clog up and as I bought another one for the boat club system I got a good trade price which wasn't that much more that swapping the 12v Jabsco for a Whale. Apart from the niggling start-up issue I'm delighted with it.

 

 

12 minutes ago, Onewheeler said:

It should work, my only reservation would be that it's not clear how it would like a modified square wave input. A PSW invertor should be OK. At 1 kW you'll need a heat sink, but not a big one.

 

Let us know how you get on! It might be a useful means of running a domestic macerator toilet from an invertor.

My inverter is pure sine wave. Where would I fit the heat sink and would I need one given that the pump never runs continuously for more than a few minutes usually less.

Edit just found data sheet explaining heat sink stuff. I will contact RS
http://docs-europe.electrocomponents.com/webdocs/002c/0900766b8002c42b.pdf

Edited June 29, 2017 by Midnight
further info

[Onewheeler]

2 hours ago, Midnight said:

My inverter is pure sine wave. Where would I fit the heat sink and would I need one given that the pump never runs continuously for more than a few minutes usually less.

 

Looking at the spec sheet you might just get away without one, but my preference would be to fit one. Either find a handy piece of *flat* steel to mount it on, or buy a heatsink from RS or wherever. If the heatsink is bigger in area than the device it should have a low enough thermal resistance for your application (unless you then wrap it up i foam!) You might find a CPU heatsink that could be adapted.

[dmr]

Sorry, my misunderstanding, I thought we were talking about a pump to drain the shower. For a pumpout a mains driven pump makes a lot of sense.

As said somewhere above, if its all ok when running the engine this does suggest that the 12 wiring to the inverter is at least part of the problem. Is there any potential for improvement here? Are you  really  sure the connectors are all good clean and tight? Are the cables thick enough? Is the isolator switch in good condition? and are the batteries really ok?. Is running the engine to start the pump a problem? 

But.... that softstart module looks like a nifty device, buy one and give it a go. Question to ask yourself....if it does not work or blows up is losing £40 a disaster for you or just the reasonable cost of an interesting experiment?  You might get away without a heatsink, run it and feel how hot it gets (keeping fingers well away from the mains).

..............Dave

[hounddog]

Thinking aloud; i wonder whether a MSW which, in theory, transmits more power with its harmonics, would struggle less? 

[stegra]

I recently replaced an old modified sine wave inverter with a 'soft start' pure sine wave inverter. It powers the fridge in my campervan and is switched via the thermostat in the fridge. There's a noticeable difference. Gone are the days of the lights going dim when the fridge kicks in or the inverter switching off in the night because the batteries can't cope.

It's only a cheapy from China and a little more noisy because it has a cooling fan but then it's about one sixth the size. Don't know if it uses the same tech as this device but I'm very pleased with it. You can actually hear it build up in a few steps.

[dmr]

57 minutes ago, hounddog said:

Thinking aloud; i wonder whether a MSW which, in theory, transmits more power with its harmonics, would struggle less? 

Where motors are concerned the energy in the harmonics is generally at the wrong frequency so of little help, it just makes everything get hot.

Some of the Chinese pure sine wave inverters are now really cheap so not much point in using MSW, just buy from a reputable dealer and rate very conservatively, if you need 1000W then get a 2kW jobbie.

and, now that the conservatives are the foolish and reckless party do we have to stop using the word conservative to mean safe with a big safety margin????

..............Dave

[Midnight]

UPDATE
I talked to United Automation Technical Dept today but he said they would be concerned that the SSC-25 Soft Start Controller will not be suitable for an inverter situation. However he did tell me there is another newer, more robust, (more expensive?) product available with a relay bypass  - but not yet on their website - so is going to send details via email.

Edited June 30, 2017 by Midnight

[smileypete]

Might be able to use a soft start board:

http://www.ebay.co.uk/itm/High-Power-40A-4000W-Soft-Start-Power-Supply-Board-for-Class-A-Amplifier-/331830475908

They use an NTC thermistor (12 ohms in the above one, so may need up to a 3kW inverter) to limit inrush then bypass with a delay relay, before the thermistor gets as hot as lava.

Cheeper than the above module, but a lot less user freindly and reliability/safety may be a bit of an unknown....no free lunch here I'm afraid.

Edited July 1, 2017 by smileypete

[Midnight]

On ‎01‎/‎07‎/‎2017 at 15:51, smileypete said:

Might be able to use a soft start board:

http://www.ebay.co.uk/itm/High-Power-40A-4000W-Soft-Start-Power-Supply-Board-for-Class-A-Amplifier-/331830475908

They use an NTC thermistor (12 ohms in the above one, so may need up to a 3kW inverter) to limit inrush then bypass with a delay relay, before the thermistor gets as hot as lava.

Cheeper than the above module, but a lot less user freindly and reliability/safety may be a bit of an unknown....no free lunch here I'm afraid.

Thanks for the info but don't know enough about these things to take a chance. Good price though.
PS I'll post the info from United Automation when it arrives.

[Midnight]

As promised details of the soft starter recommended for use with an inverter by United Automation technical fella

The part code is A403156

The Price is £105.00
Carriage is £10.50

direct from United Automation
http://www.united-automation.com/

User manual link below

 

X20012 (1)-SSC-6KW_docx.pdf

Edited July 13, 2017 by Midnight

[WotEver]

And has it done the trick?