Beta Travel Power

[Jayseaess]

Pro and cons if you have one fitted?

[nicknorman]

The pros are lots of power available (3.5 kW or 5 kW) with the engine running and no risk of depleting your batteries. The cons are the cost, and that the alternator is permanently running when the engine is running thus creating a bit of drag and increased fuel consumption. Brushes and to a lesser extent the drive belt wears all the time the engine is running. A minor con is that the output is centre tapped (as opposed to live and neutral) which does seem to upset the likes of my iPad touchscreen when it's being charged via the TP.

[ditchcrawler]

The pros are lots of power available (3.5 kW or 5 kW) with the engine running and no risk of depleting your batteries. The cons are the cost, and that the alternator is permanently running when the engine is running thus creating a bit of drag and increased fuel consumption. Brushes and to a lesser extent the drive belt wears all the time the engine is running. A minor con is that the output is centre tapped (as opposed to live and neutral) which does seem to upset the likes of my iPad touchscreen when it's being charged via the TP.

Maybe it needs to be fed through an IT

[Bunny]

We had ours repaired/replaced sometimes under guarantee , sometimes not every.2 years at 650 to 800 pds a repair , expensive hobby . Gave up in the end . Bunny.

[trackman]

Ours is nearly ten years old and over 4200 hours running. It's been brilliant.

The advice of an expert who repairs them was that it should do 6000 hours before needing servicing.

 

It does depend which type of alternator you have/get though, he said. Ours is an Iskra iirc (not on board tonight so can't check) and they were said to be good. Earlier ones (Bosch maybe?) were good for only 4000 hrs as I recall from his advice.

 

I worry about the bearings & bushes, but a recent quick check suggested no oroblems with ours yet. The drive belt is a chunky multi-vee job. I changed ours after about 5 years and 3000 ish hours but the old one was perfectly good to keep as a spare.

 

Ours is in a traditional style engine room, which does mean it's kept warm and dry mostly, and may help compsred with installation under a cruiser stern deck.

[nicknorman]

Maybe it needs to be fed through an IT

No doubt that would fix it, but it's cheaper to just not use the iPad when it's charging via the TP!

 

We had ours repaired/replaced sometimes under guarantee , sometimes not every.2 years at 650 to 800 pds a repair , expensive hobby . Gave up in the end . Bunny.

Ours is coming up to 5 years / 20000 engine hours and no problem so far. FLW!

[ditchcrawler]

No doubt that would fix it, but it's cheaper to just not use the iPad when it's charging via the TP!

 

 

 

Did you see the thread about the possible centre tapped inverter?

[Top cat]

I did a long term fuel consumption test with and without out our travelpower being driven from the engine and could detect no difference in the overall fuel consumption. Yes I can detect the extra power being drawn when the kettle goes on but its much the same whether it's the alternator or travelpower providing the power.

 

I like ours which has run for 2500 hrs with out major problems, all that occurs is the warning light comes on at idle sometimes which is caused by a poor connection to the unit which I must get round to replacing sometime.

 

Top Cat

[Keith M]

If the output of the travel power is not distributed via an Isolation Transformer then all circuit breakers and socket must be doubled poled.

 

I under standed the the latest version of the travel power is not a centre tapped device.

 

Therefore double pole protection will not be required

 

Most installers do not understand how to provide the correct AC protection

 

Keith

Edited October 27, 2015 by Keith M

[nicknorman]

If the output of the travel power is not distributed vai an Isolation Transformer then all circuit breakers and socket must be doubled poled.

 

I under standed the the latest version of the travel power is not a centre tapped device.

 

Therefore double protection will not be required

 

Most installers do not understand how to provide the correct AC protection

 

Keith

It's an interesting point since certainly ours, and I suspect many others, doesn't go via an IT. That said, thinking about it the RCD / breaker does of course have both live and neutral going through it, I have never thought to check whether it's double pole switched or not. The sockets are certainly normal types which I believe only switch the live.

 

I don't recall the installation instructions mentioning an IT / double pole switching (the manual is on the boat, I'm at home) but I can certainly see the logic behind your comments. I'll check when next on the boat.

 

In our case the TP feeds through the Mastervolt Mass Combi, which is quite happy with the centre tapped power coming in. I have never tried the power assist function but I wonder how the Combi would cope with assisting the centre-tapped TP input.

[Keith M]

I am not sure if the RCD would funtion correctly via the travel power

 

When conducting electrical inspection my test equipment will not funtion correctly on the out put of a TP

 

So to-date I have not been able to test an RCD via a TP

 

As I stated most installers do not understand how to design correct AC protection

 

Keith

[nicknorman]

I am not sure if the RCD would funtion correctly via the travel power

 

When conducting electrical inspection my test equipment will not funtion correctly on the out put of a TP

 

So to-date I have not been able to test an RCD via a TP

 

As I stated most installers do not understand how to design correct AC protection

 

Keith

I can't see a reason why the RCD wouldn't work with a TP. The RCD is just looking for a mismatch in current between the live and neutral. The voltages don't come into it. The TP is midpoint-to-earth bonded, so any connection from either live or neutral, to earth, that gives an earth current of greater than 30mA (or whatever) will trip the RCD.

 

The only thing that might be affected is the RCD test button - if it's the type that puts a resistor between live and earth then of course said resistor will only have half the normal voltage across it, so have half the current.

 

Of course it's worth pointing out that the upside of the centre tapping is that the live is only at 115v or so, compared to earth, so just like the American system or that used on building sites, touching live and earth is unlikely to give a fatal shock. You would have to touch both live and neutral to receive a "mains" level shock.

Edited October 27, 2015 by nicknorman

[MoominPapa]

Of course it's worth pointing out that the upside of the centre tapping is that the live is only at 115v or so, compared to earth, so just like the American system or that used on building sites, touching live and earth is unlikely to give a fatal shock. You would have to touch both live and neutral to receive a "mains" level shock.

 

The system used on building-sites is 120v live-neutral _and_ centre-tapped, reducing the line-earth voltage to 60v by the same mechanism, so more safe (twice as safe?) as a 240v CT system.

 

MP.

[nicknorman]

The system used on building-sites is 120v live-neutral _and_ centre-tapped, reducing the line-earth voltage to 60v by the same mechanism, so more safe (twice as safe?) as a 240v CT system.

 

MP.

Ok, well going back to my earlier post it's like the mains in the USA then, not a building site.

[OldGoat]

IME -

Earlier versions of the TP had reliability problems which - it is said were fixed some time ago.

There were also comments about the reliability or otherwise between the two models.

There's a Very-Nice-Man in Atherstone who fits them to vans - so it's not exclusively a boating device. He also does repairs to them.

 

I had an early similar device - a 5KW Sea Power - brilliant device, no problems with driving it - even though in those days it had to be 'B' section V belts. One day the electronics died completely. No replacement chips available. RIP Sea Power....

 

It needs a fairly substantial mounting arrangement - which Beta do using a rail rather than attachments to the engine body (?) - so not an easy aftermarket option.

[ditchcrawler]

 

 

The only thing that might be affected is the RCD test button - if it's the type that puts a resistor between live and earth then of course said resistor will only have half the normal voltage across it, so have half the current.

 

 

Which could be why the test equipment dosen.t work as it may not be putting the full 30ma to earth. I think the test button just unbalances the live neural current and doesn't rely on earth at all.

[nicknorman]

Which could be why the test equipment dosen.t work as it may not be putting the full 30ma to earth. I think the test button just unbalances the live neural current and doesn't rely on earth at all.

Yes to the first bit, as to the second bit I think there are some variations, but in some cases it sends some live current to earth thus unbalancing the live and neutral. You can't have different currents in live and neutral unless some current is going somewhere else, and to earth is the only other possibility. However if you are saying it doesn't measure the earth current directly, I agree, and so the earth doesn't have to route through the breaker, but it does have to go to the breaker if it's that type. Other types send test current between live on one side of the inductor to the neutral on the other, those don't need earth at all. Not sure which type predominates!

Edited October 27, 2015 by nicknorman

[nicknorman]

It needs a fairly substantial mounting arrangement - which Beta do using a rail rather than attachments to the engine body (?) - so not an easy aftermarket option.

Out of interest this is the front of our (new, never run) engine showing the attachment frame for the alternators. If you were going to retrofit I think it would be a lot easier to get the full installation kit from Beta rather than trying to cobble something together yourself, since a lot of power goes through the belt and hence a lot of mechanical load.

 

 

TP is the one on the far right. You can see that the 175A alternator (far left) which gives roughly 2kw, is a bit larger than the 3.5kw TP alternator. The joys of high voltage!

Edited October 27, 2015 by nicknorman

[dmr]

 

Ours is coming up to 5 years / 20000 engine hours and no problem so far. FLW!

 

I think you mean 2000 hours, even ours has not got to 20000 yet..

It has however done over 14,000 hours and has had a rebuild or two over that time.

The way to get a long life is to fit new beariings every two or three years, and sometimes new sliprings.

We have the older Bosch unit and the last time the bearings were replaced I got them on eBay. A man near Devizes then fitted them (often needs a press) for a tenner.

 

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

[nicknorman]

I think you mean 2000 hours, even ours has not got to 20000 yet..

It has however done over 14,000 hours and has had a rebuild or two over that time.

The way to get a long life is to fit new beariings every two or three years, and sometimes new sliprings.

We have the older Bosch unit and the last time the bearings were replaced I got them on eBay. A man near Devizes then fitted them (often needs a press) for a tenner.

 

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

Oops, well what's the odd zero between friends!

 

Yea maybe I should take it off and check the bearings/ slip rings / brushes. I've got a week pottering about on the boat in early December...

[Keith M]

I can't see a reason why the RCD wouldn't work with a TP. The RCD is just looking for a mismatch in current between the live and neutral. The voltages don't come into it. The TP is midpoint-to-earth bonded, so any connection from either live or neutral, to earth, that gives an earth current of greater than 30mA (or whatever) will trip the RCD.

 

The only thing that might be affected is the RCD test button - if it's the type that puts a resistor between live and earth then of course said resistor will only have half the normal voltage across it, so have half the current.

 

Of course it's worth pointing out that the upside of the centre tapping is that the live is only at 115v or so, compared to earth, so just like the American system or that used on building sites, touching live and earth is unlikely to give a fatal shock. You would have to touch both live and neutral to receive a "mains" level shock.

I will have to disagree some of the above.

 

IT'S MILLS THAT KILL

 

The above was drummed into me at college many years ago and still holds good to-day

 

With the way in which AC is generated with in a TP I believe there is not an earth on the output just a centre point of a transformer

 

no where for the fault current to go.

 

The reason why my test equipment will not function correctly is that it is looking for a 0 & 230 AC volts not 115 AC volt on both legs

 

Some test buttons are just a mechanical check

 

Keith

[Keith M]

1. Under normal operation, when there is no magnetic field in the core, no electricity flows through the search coil (gray) or relay (blue).
2. Suppose you cut through the live wire (green) with your garden shears—and suppose it takes a tenth of a second for you to chop right through.
3. During that tenth of a second, just as you're starting to cut, there is a current imbalance between the live and neutral cables. More current flows through the neutral wire (orange) than through the live wire (green), so the neutral wire produces a greater magnetic field (red arrow) in the iron core than the live wire does (blue arrow).
4. The two magnetic fields no longer cancel out. The net magnetic field in the core causes an electric current to flow in the search coil (gray), which activates the relay (blue).
5. The relay snaps open breaking the incoming circuit cables and stopping all power from flowing in as little as 30 milliseconds—far faster than you can cut the cable

Above is an explanation of the workings of an RCD. As with a TP the output current is both flowing in the same direction in both wires to my mind so unable too cancel the magnetic effect in the RCD.

 

Keith

[dmr]

The two output phases must surely be referenced to the earth otherwise they could float about all over the place and be a real hazzard, and also hurt the filter components built into so much modern electronics.

I think the old black box unit (don't know about the silver box) does not really have a centre tapped transformer. The 3 outputs from the alternator will go to a bridge rectifier to produce two DC (ish) rails at about +/-170 volts. These are then switched using a big transistor jobbie to produce the 120 volt sine waves. There are two big torroidal things but I reckon these are chokes.

 

Any fault current (from an unfortunate human) must go to earth that's what an electric shock usually is. As long as the breaker responds to a difference in the live and neutral currents then all is well. I suspect a person who touches live and neutral is in trouble but is that not the case with a standard domestic supply?.

 

Only issue I can see is having live 120 volts inside equipment when only a single pole switch is used.

 

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

[nicknorman]

I will have to disagree some of the above.

 

IT'S MILLS THAT KILL

 

The above was drummed into me at college many years ago and still holds good to-day

 

With the way in which AC is generated with in a TP I believe there is not an earth on the output just a centre point of a transformer

 

no where for the fault current to go.

 

The reason why my test equipment will not function correctly is that it is looking for a 0 & 230 AC volts not 115 AC volt on both legs

 

Some test buttons are just a mechanical check

 

Keith

Yes it is milliamperes that kill, but to get that you need voltage. How much depends on resistance of course, but for a typical human skin resistance 110v probably is below the level to give fatal current. Probably if you wired yourself up with pads and conductive gel around your heart you could make it fatal, but you would have to try quite hard!

 

On our TP the output is centre tapped and that cente tap is connected to hull so it is earthed. Otherwise the live and neutral would just be floating and the answer would be an NE bond. Which it isn't! As we know there have been some interations of TPs over the years and perhaps they are not all thus.

 

• Under normal operation, when there is no magnetic field in the core, no electricity flows through the search coil (gray) or relay (blue).
• Suppose you cut through the live wire (green) with your garden shearsand suppose it takes a tenth of a second for you to chop right through.
• During that tenth of a second, just as you're starting to cut, there is a current imbalance between the live and neutral cables. More current flows through the neutral wire (orange) than through the live wire (green), so the neutral wire produces a greater magnetic field (red arrow) in the iron core than the live wire does (blue arrow).
• The two magnetic fields no longer cancel out. The net magnetic field in the core causes an electric current to flow in the search coil (gray), which activates the relay (blue).
• The relay snaps open breaking the incoming circuit cables and stopping all power from flowing in as little as 30 millisecondsfar faster than you can cut the cable

Above is an explanation of the workings of an RCD. As with a TP the output current is both flowing in the same direction in both wires to my mind so unable too cancel the magnetic effect in the RCD.

 

Keith

That is a terrible explanation of how an RCD works, it is completely wrong. If you interrupt the current in one conductor, it simultaneously stops in the other one. It is a fundamental rule of physics that current is preserved around a circuit (Kirchhoff? I need to check!). By that explanation, the RCD would trip every time you turned off a single-pole switch.

 

The RCD works by detecting some current bypassing the live or neutral and instead going via earth (and maybe via your body!). If there is no earth, an RCD can't work because there is no other path for the current.

Edited October 27, 2015 by nicknorman

[by'eck]

 

As with a TP the output current is both flowing in the same direction in both wires to my mind so unable too cancel the magnetic effect in the RCD.

 

Keith

 

Have a think again Keith. With a centre tap earthed supply accidentally touching either leg will result in current flowing through your (earthed) body, so increasing the current flowing in the leg you touch, creating in turn the imbalance needed to trip an RCD.

 

Being half the voltage I would surmise this would likely be half the current compared with N/E bonded system. On the other hand you have twice the possibility of tripping the RCD or getting a shock if it fails.

 

Agree though its the volts that jolts but the mills that kills