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48v alternators


Antrepat
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37 minutes ago, Antrepat said:

 

Yep, I know.  Just as well I like a challenge, eh?  Look, if it turns out not to be feasible or affordable, that'll be disappointing but I'll just have to accept it.  I enjoy the process of evaluation in itself and I hope I always welcome straight "that isn't realistic, think again" talkings-to (@Tony Brooks).  I'm aware that there is a risk of thinking something looks simple and cheap but the detail will reveal why it's not, so it's that detail I'm working on assembling.

 

 

I thought that too, having reviewed the full range.  Any comment on water-cooled vs. air-cooled, especially as continuous running would be at a power much less than the "continuous running" rating?

 

Voltsport say "To run at or beyond the continuous figures, a decent cooling system is needed", but "Continuous running: 1210RPM, 90Nm, 12.4kW / 15.3HP to the propeller", which is vastly more than the 3 or 4kW I'd typically be doing to potter along at 3mph.  (EDIT: but that is a 205W_08016 motor.)

 

Mountings: Voltsport's Direct Drive Kit appears to come with a mounting frame.  I wasn't proposing to just buy a motor and take it from there, obviously.

 

 

Good.  Do you mean boat speed or rpm?  Attached graph from the 205W_12013 data sheet suggests 3kW at 250rpm, 7kW at 500rpm, 14kW (surely peak for our needs) at 1000rpm, which I thought fitted in with the advice about power within a <1000rpm spin speed range with a suitable propeller.  Incidentally, what values did you use when you ran that propeller calculator?

 

image.png

 

Like with a diesel engine, it's the power a propeller absorbs at a particular rpm that matters, not the power the engine can generate. Propeller power goes up roughly as rpm^3 (actually a bit faster according to measurements) and you want it to match motor power at whichever power/rpm combination you want to use. This is usually the point at which torque starts to fall and which is where the motor is specified, in this case it's 14kW (18.7hp) at 1080rpm. So to work out rpm for 3kW multiply by the cube root of 3/14, which gives 650rpm.

 

For the propeller calculation I used 60' x 7' x 2' for the hull and 40000lbs (18 tons) for the weight, you can put your own numbers in. I believe the Vicprop calculator takes account of both hull profile and skin drag, and the results if you vary the boat length/weight are interesting to say the least -- don't forget these figures are for deep water (e.g. a river) because this is the only time you'll ever need full power...

 

72' x 7' x 2' 48000lbs 6.5kts 17.2"x11.7" (3 blade)

60' x 7' x 2' 40000lbs 6.3kts 17.2"x11.4"

48' x 7' x 2' 32000lbs 6.1kts 17.2"x11.1"

36' x 7' x 2' 24000lbs 5.8kts 17.2"x10.7"

 

Water cooling (if available) is a good idea for two reasons; one is it avoids the need for a cooling fan (noise), the second is that the heat goes into the canal (skin cooling) not the engine compartment -- and only a small cooler is needed, see attached photo.

 

You're right that it isn't needed unless you run for long periods (e.g. more than 30 minutes) at close to full power, which will never happen on a narrowboat unless you find yourself going upriver on the Thames or Trent or Severn or Avon or Ribble link or... [fill in others of your choice]. If you do water cool then the cooling water pump can be triggered by motor temperature or power output, it will never run when cruising on a still canal.

 

 

lockers stern.jpg

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25 minutes ago, IanD said:

Water cooling (if available) is a good idea for two reasons; one is it avoids the need for a cooling fan (noise), the second is that the heat goes into the canal (skin cooling) not the engine compartment -- and only a small cooler is needed, see attached photo

Not sure where the skin tank is in this picture.  I have one already but I'm guessing the motor cooling and the engine cooling can't be intermingled...

 

26 minutes ago, IanD said:

unless you find yourself going upriver on the Thames or Trent or Severn or Avon or Ribble link or... [fill in others of your choice]

The exit from my mooring is directly onto the Calder.  The Calder & Hebble Navigation has stretches of the Calder.  Then there's the Aire, the Ouse (tidal to Naburn)...I'm not planning to navigate against any tidal flows but I do need the power for manoeuvre on rivers.

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13 minutes ago, Antrepat said:

Not sure where the skin tank is in this picture.  I have one already but I'm guessing the motor cooling and the engine cooling can't be intermingled...

 

The exit from my mooring is directly onto the Calder.  The Calder & Hebble Navigation has stretches of the Calder.  Then there's the Aire, the Ouse (tidal to Naburn)...I'm not planning to navigate against any tidal flows but I do need the power for manoeuvre on rivers.

 

It's the small rectangle with the two capped-off connections under where the motor will go.

 

If you're regularly going out onto rivers -- even non-tidal -- I'd recommend designing the system so you can sustain maximum power without overheating, so preferably a water-cooled motor -- also do the same for the Sevcon controller (mount it on the swim).

 

I've travelled up non-tidal rivers against reasonably strong currents in narrowboats, and the last thing I'd want is to suddenly find power reduced (or even worse, cut out) because of motor/controller overheating... 😞

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12 minutes ago, Antrepat said:

Not sure where the skin tank is in this picture.  I have one already but I'm guessing the motor cooling and the engine cooling can't be intermingled...

 

 

Providing the skin tank is large enough (many are not) then remember all skin tank cooled boats with hydraulic gearboxes intermingle the gearbox cooling and engine cooling. As long as the electric motor gets its cooling water direct from the skin tank, and then it goes on to the engine I can't see it won't work providing the pressure caps are arranged so they are both the same or one is a little higher than the other. I think both engine water pumps will play nicely if they are centrifugal types, not so sure if one is a rubber impeller type. If you used a suitable sized heat exchanger and pump for the motor then it would not be much different from the gearbox oil coolers in the engine cooling circuit. However, once more it is unconventional with little real practical experience.

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10 minutes ago, Tony Brooks said:

 

Providing the skin tank is large enough (many are not) then remember all skin tank cooled boats with hydraulic gearboxes intermingle the gearbox cooling and engine cooling. As long as the electric motor gets its cooling water direct from the skin tank, and then it goes on to the engine I can't see it won't work providing the pressure caps are arranged so they are both the same or one is a little higher than the other. I think both engine water pumps will play nicely if they are centrifugal types, not so sure if one is a rubber impeller type. If you used a suitable sized heat exchanger and pump for the motor then it would not be much different from the gearbox oil coolers in the engine cooling circuit. However, once more it is unconventional with little real practical experience.

 

I wouldn't recommend merging the cooling systems, especially if the electric motor one only runs occasionally (as does the generator, and not even at the same time) -- apart from backflow there may be issues with temperature or coolant incompatibility or electrolytic corrosion, depending on materials. Engiro recommended cooling is water/glycol 50/50, 8 l/min, ≤ 45°C, ≤ 0.5 bar.

 

The electric motor only needs a tiny skin tank (see photo) since it dumps less than 1kW of heat into it, the generator will dump more than 10kW into it (depending on size) so is far bigger -- you can see this on the port side swim to the right.

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2 minutes ago, IanD said:

 

I wouldn't recommend merging the cooling systems, especially if the electric motor one only runs occasionally (as does the generator, and not even at the same time) -- apart from backflow there may be issues with temperature or coolant incompatibility or electrolytic corrosion, depending on materials.

 

The electric motor only needs a tiny skin tank (see photo) since it dumps less than 1kW of heat into it, the generator will dump more than 10kW into it (depending on size) so is far bigger -- you can see this on the port side swim to the right.

 

Hence, my suggesting a heat exchanger solution so no coolant mixes

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5 minutes ago, Tony Brooks said:

 

Hence, my suggesting a heat exchanger solution so no coolant mixes

 

Doesn't work if the motor needs cooling (pump running) but the generator is off. Separate skin tanks are much simpler, with shorter piping, and less risk of going wrong...

Edited by IanD
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5 hours ago, Antrepat said:

Perhaps I've looked in the wrong places, but I haven't seen any 230v AC - 48v DC chargers that can deliver 0.3C for a 400Ah battery.

I have just found this, however: https://www.meanwell.eu/webapp/product/search.aspx?prod=RST-10000

 

...with remote on/off, which means the REC Q BMS can signal it to terminate when a predetermined SOC is achieved...

 

...but it's £3k+ so that's the cost of the AC generator plus the cost of this to rectify and transform...

 

So is that better than taking the components of a tried and tested marine generator, and substituting a different alternator that delivers the actual voltage DC needed, keeping everything else the same (and choosing the uprated version to compensate for lower efficiency of lower-voltage alternators)?

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3 hours ago, Antrepat said:

I have just found this, however: https://www.meanwell.eu/webapp/product/search.aspx?prod=RST-10000

 

...with remote on/off, which means the REC Q BMS can signal it to terminate when a predetermined SOC is achieved...

 

...but it's £3k+ so that's the cost of the AC generator plus the cost of this to rectify and transform...

 

So is that better than taking the components of a tried and tested marine generator, and substituting a different alternator that delivers the actual voltage DC needed, keeping everything else the same (and choosing the uprated version to compensate for lower efficiency of lower-voltage alternators)?

You do realise that needs a 3-phase input, so you'd need a 3-phase AC generator? Most generators at the power levels you're looking for are single-phase, 3-phase ones do exist but are much harder to find -- unless you get a new one, which is out of your budget.

 

I think you're going round in circles here, trying to find a solution that doesn't exist -- one that is relatively cheap, can be put together out of available components, is reliable and easy to control for LFP battery charging, will fit in the space you have, and doesn't need deep expertise in electrics/electronics/software. These requirements seem to be mutually incompatible... 😞

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2 minutes ago, IanD said:

You do realise that needs a 3-phase input, so you'd need a 3-phase AC generator? Most generators at the power levels you're looking for are single-phase, 3-phase ones do exist but are much harder to find -- unless you get a new one, which is out of your budget.

Yep.  More expense for the AC+separate transformation/rectification solution, then.  I researched this further to illustrate that this is a more expensive solution.

 

12 minutes ago, IanD said:

think you're going round in circles here, trying to find a solution that doesn't exist -- one that is relatively cheap, can be put together out of available components, is reliable and easy to control for LFP battery charging, will fit in the space you have, and doesn't need deep expertise in electrics/electronics/software. These requirements seem to be mutually incompatible...

I'm not going round in circles.  I'm clear what I think is the right solution, and it's the one you seemed to recommend too: using an OTS genset like the Beta 6/2 as an indicative template but substituting a different axial alternator to avoid all the issues with transformation and rectification of AC or Heath Robinson belt and bracket arrangements.  The Sincro alternator and indeed the engine with the right start/stop controller will respond to a start/stop signal from a BMS that can generate it, like the REC ones can.  It also has (even if the exact details of the electrics need clarifying) a voltage and a current control function, if just start/stop isn't graceful enough.  Unless there is some kind of high-falutin' wizardry about that genset that means it has some complicated  and expensive other element beyond an engine, an alternator and engine control, I fail to see where the massive hidden cost is beyond the cost of one of those engines (£2k + VAT), the cost of the alternator (£850), and the cost of the engine control equipment (£don't know but I'll find out).  Unless that alternator is unreliable or the rig doesn't fit in the space available, what am I missing?

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2 minutes ago, Antrepat said:

Yep.  More expense for the AC+separate transformation/rectification solution, then.  I researched this further to illustrate that this is a more expensive solution.

 

 

You can get a readily available 48 volt 120 amp battery charger for £400 but it requires a 3-phase supply.

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9 hours ago, Antrepat said:

If you don't mean something like this monster, could you perhaps drop a link to the one you mean?

 

This one is only 24v 120a but there was a 48v version listed previously - it must have been bought.

 

Varta Forklift Truck Battery Charger 24V 140 Amp Fork Lift Charger | eBay

 

 

Then there is this one listed 48v 140a but it is a big one. If you are looking for a big powerful charger then it is going to be physically big.

 

Hoppecke 3 Phase 48v 180amp Forklift Truck Battery Charger HysterYale Linde | eBay

 

 

Or, a 'baby one' at 48v 55 amps (single phase supply)

 

Forklift Battery Charger Chloride 48V All working 240V 16A Plug | eBay

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2 hours ago, Alan de Enfield said:

 

This one is only 24v 120a but there was a 48v version listed previously - it must have been bought.

 

Varta Forklift Truck Battery Charger 24V 140 Amp Fork Lift Charger | eBay

 

 

Then there is this one listed 48v 140a but it is a big one. If you are looking for a big powerful charger then it is going to be physically big.

 

Hoppecke 3 Phase 48v 180amp Forklift Truck Battery Charger HysterYale Linde | eBay

 

 

Or, a 'baby one' at 48v 55 amps (single phase supply)

 

Forklift Battery Charger Chloride 48V All working 240V 16A Plug | eBay

 

The problem with all those is that a) they're 3-phase b) they're *unsurprisingly!) big and heavy c) they're designed to do daily charges on traction lead acid batteries (2V flooded tubular cells) which really like high voltages and gassing, so no need for float settings.

 

Used as is they'd totally destroy LFP cells in one charge cycle, and they're likely to be difficult (maybe impossible) to repurpose for safe long-life LFP charging.

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12 hours ago, Antrepat said:

Yep.  More expense for the AC+separate transformation/rectification solution, then.  I researched this further to illustrate that this is a more expensive solution.

 

I'm not going round in circles.  I'm clear what I think is the right solution, and it's the one you seemed to recommend too: using an OTS genset like the Beta 6/2 as an indicative template but substituting a different axial alternator to avoid all the issues with transformation and rectification of AC or Heath Robinson belt and bracket arrangements.  The Sincro alternator and indeed the engine with the right start/stop controller will respond to a start/stop signal from a BMS that can generate it, like the REC ones can.  It also has (even if the exact details of the electrics need clarifying) a voltage and a current control function, if just start/stop isn't graceful enough.  Unless there is some kind of high-falutin' wizardry about that genset that means it has some complicated  and expensive other element beyond an engine, an alternator and engine control, I fail to see where the massive hidden cost is beyond the cost of one of those engines (£2k + VAT), the cost of the alternator (£850), and the cost of the engine control equipment (£don't know but I'll find out).  Unless that alternator is unreliable or the rig doesn't fit in the space available, what am I missing?

 

There are lots of hidden material costs that you haven't included such as contactors, system controller, display, throttle, mounting frames/couplings (do you have a machine shop?), generator control -- and that's before you get onto similar costs for the drive system, you can't just connect a Sevcon controller up to the motor/battery and turn it on.

 

The other big problem is I think you're greatly underestimating the difficulty of putting this all together especially if all the parts are not used as-is/off-the-shelf -- if you just look at a conventional generator there are a lot of grobbly little bits needed to control the engine and alternator (AVR etc) and make it all start and stop under control and protect it and...

 

Designing and building your own generator (which is effectively what you're proposing) is a big job, especially if you want to use it for charging LFP batteries -- which is difficult enough on its own, ask nicknorman. Doing the same for the electric drive system is a similar complexity, except the currents are much higher so more opportunity for things to go wrong.

 

Doing all this together and ending up with a safe and reliable system is a *big* design/development job -- I looked at doing this myself just for the drive system, and it was the little things like programming the controller and display that were the stumbling blocks, not buying the big bits like the motor and controller.

11 minutes ago, Alan de Enfield said:

 

No they are not 3-phase.

Only 1 of the 3 is 3-phase.

 

They are just examples of 'cheap' chargers that the OP asked me to post.

 

3-phase isn't the biggest problem in itself -- except that means him sourcing a 3-phase generator small enough to fit in the space he's got which is probably impossible, never mind the size of the charger...

 

Trying to take a dumb forklift charger intended to charge 2V flooded lead-acid tubular cells every night and making it work safely long-term with LFP batteries is a *far* bigger problem... 😞

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9 hours ago, Alan de Enfield said:

This one is only 24v 120a but there was a 48v version listed previously - it must have been bought.

Varta Forklift Truck Battery Charger 24V 140 Amp Fork Lift Charger | eBay

Then there is this one listed 48v 140a but it is a big one. If you are looking for a big powerful charger then it is going to be physically big.

Hoppecke 3 Phase 48v 180amp Forklift Truck Battery Charger HysterYale Linde | eBay

Or, a 'baby one' at 48v 55 amps (single phase supply)

Forklift Battery Charger Chloride 48V All working 240V 16A Plug | eBay

 

My battery will be LFPs.  Unless I'm mistaken, these chargers are all for LA traction batteries.  They will not operate at the right voltages, nor will they terminate charge based on a precise voltage/current combination threshold, nor will they probably take an external control signal to shut off if the BMS alarms and disconnects the LFPs.

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7 hours ago, IanD said:

There are lots of hidden material costs that you haven't included such as contactors, system controller, display, throttle, mounting frames/couplings (do you have a machine shop?), generator control -- and that's before you get onto similar costs for the drive system, you can't just connect a Sevcon controller up to the motor/battery and turn it on.

 

The other big problem is I think you're greatly underestimating the difficulty of putting this all together especially if all the parts are not used as-is/off-the-shelf -- if you just look at a conventional generator there are a lot of grobbly little bits needed to control the engine and alternator (AVR etc) and make it all start and stop under control and protect it and...

 

Designing and building your own generator (which is effectively what you're proposing) is a big job, especially if you want to use it for charging LFP batteries -- which is difficult enough on its own, ask nicknorman. Doing the same for the electric drive system is a similar complexity, except the currents are much higher so more opportunity for things to go wrong.

 

Doing all this together and ending up with a safe and reliable system is a *big* design/development job -- I looked at doing this myself just for the drive system, and it was the little things like programming the controller and display that were the stumbling blocks, not buying the big bits like the motor and controller.

 

I'm not belittling the complexity.  I'm not expecting to buy a bunch of stuff and connect all together with wires and prayers and have it just work.  I know sophisticated devices like BMSs and motor controllers will have to be configured according to a well-planned, well-informed scheme.  I know, and I hoped this at least was evident, that LFPs have very particular management and charging requirements.  I know a generator set is not really just an alternator bolted to an engine with a start button.  I know I'll need all manner of sundries like contactors, control interface devices, hardware, fusing, junction boxes, bus bars, and terminals.  I'm prepared for it to take a long time and a lot of careful research and planning and acquisition of new knowledge and skills, but this isn't my first rodeo - I've been writing computer software, building databases, analysing data, and engaging with all manner of practical technical matters for 49 years, and I am capable of doing the homework, designing at a system and a component level, formulating and evaluating options, considering multiple factors, resolving conflicting requirements and, above all, having the patience to wait until I am properly prepared before proceeding.  I humbly want to give it a go, I will graciously accept any advice offered, and like I said before, if it's not feasible, I will accept that, but please don't think I am going blundering into this like a damned fool who has more money than sense.  If that's the impression you've got of me then I've communicated badly about my attitude and intentions.

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5 hours ago, Antrepat said:

 

I'm not belittling the complexity.  I'm not expecting to buy a bunch of stuff and connect all together with wires and prayers and have it just work.  I know sophisticated devices like BMSs and motor controllers will have to be configured according to a well-planned, well-informed scheme.  I know, and I hoped this at least was evident, that LFPs have very particular management and charging requirements.  I know a generator set is not really just an alternator bolted to an engine with a start button.  I know I'll need all manner of sundries like contactors, control interface devices, hardware, fusing, junction boxes, bus bars, and terminals.  I'm prepared for it to take a long time and a lot of careful research and planning and acquisition of new knowledge and skills, but this isn't my first rodeo - I've been writing computer software, building databases, analysing data, and engaging with all manner of practical technical matters for 49 years, and I am capable of doing the homework, designing at a system and a component level, formulating and evaluating options, considering multiple factors, resolving conflicting requirements and, above all, having the patience to wait until I am properly prepared before proceeding.  I humbly want to give it a go, I will graciously accept any advice offered, and like I said before, if it's not feasible, I will accept that, but please don't think I am going blundering into this like a damned fool who has more money than sense.  If that's the impression you've got of me then I've communicated badly about my attitude and intentions.

I don't think you've communicated badly and it seems like you actually do understand the issues -- but so many people who come on here with brilliant ideas don't, and it's not always easy to tell which category posters fall into... 😉

 

Just be aware that however much it looks like it will cost when you add up the cost of the big obvious bits, the end result will probably cost at least 50% more even of you do all the work yourself "for free" -- and if you have to pay other people to do things like machining work, maybe more. At which point it can end up not actually any cheaper than going down the standard off-the-shelf route... 😞

 

So if you want to do all this as an engineering challenge good luck to you, I'm sure people on the forum will be glad to give you advice.

 

But if you want to do it to save money you might be disappointed -- or horrified -- when you add up the actual cost including all the grobbly bits... 😉

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7 hours ago, IanD said:

But if you want to do it to save money you might be disappointed -- or horrified -- when you add up the actual cost including all the grobbly bits... 😉

 

This is even more true if you do not have enough skills and facilities to fabricate your own metalwork like mounting brackets etc.

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8 hours ago, Tony Brooks said:

 

This is even more true if you do not have enough skills and facilities to fabricate your own metalwork like mounting brackets etc.

 

Or other custom things like couplings -- when I talked to Hybrid Marine about their parallel hybrid system based on the Beta 43 (which was well over £20k...) I asked about the optional clutch between the prop shaft and gearbox/motor to allow the engine to run for charging only at the full 10kW (instead of just 3kW from the alternators with the gearbox in neutral), and was horrified when they said it was £2000 -- for a simple dog clutch and linkage, nothing special... 😞

Edited by IanD
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On 22/10/2022 at 17:33, IanD said:

 

Or other custom things like couplings -- when I talked to Hybrid Marine about their parallel hybrid system based on the Beta 43 (which was well over £20k...) I asked about the optional clutch between the prop shaft and gearbox/motor to allow the engine to run for charging only at the full 10kW (instead of just 3kW from the alternators with the gearbox in neutral), and was horrified when they said it was £2000 -- for a simple dog clutch and linkage, nothing special... 😞

 

Well, fortunately that particular one would not be one of my risks, since I'm not trying to connect the engine to the prop at all...

 

After more homework I've come back to the issue that the most challenging component is the BMS.  There are loads of dodgy cheap ones around but finding one that terminates charge based on residual current as well as voltage, and can send an external "enable/disable charge" signal, and works for 16s, is proving very difficult.  The REC Q seems to judge charge termination based on voltage and coulomb counting.  Off-topic, however.  I'd better review some of the BMS threads on here...

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  • 4 weeks later...

Don't know if this is relevant but Ford put 48V alternators on their 1.0L hybrid cars (ecoboost I think).  Plenty of used ones on Ebay for £200 - £300.

 

Couldn't be asked to read all the pages on this thread so this may have already been pointed out.  🙂

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It looks to be a starter-generator, not sure if this has any implications for its performance/efficiency as an alternator only. Could be an interesting option for conversion of hand start only vintage engines....if anybody still fits vintage engines 😀

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