20HP Bow Thruster, 24VDC Battery Bank

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20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 07 2017 11:02pm

I'm a mechanic helping research how to convert an existing bow thruster, from hydraulic to electric. The hydraulic system is shot and needs to be replaced. Captain was piloting a newer vessel he helped someone purchase and noticed how nicely it's 24 volt bow thruster worked. So now he want's to have that installed, but I can't find anything to actually make this work

I've seen some complete systems that are capable of running off of 24 volts, but their tunnels are half the size. The captain thinks his system is 20 horsepower, which means I'm looking for a unicorn motor that Google doesn't have indexed!

Maybe something that chews up 700 amps at the push of a button, only running at 20% duty-cycle? Only see about 3 or 4 threads on this site alone with anything bow-thruster-like

Is there any such motor? I've been looking and starting to get the feeling maybe I don't know how to find this one

I see systems like this: https://www.vetus.com/en/manoeuvring-sy ... -volt.html

Almost but not sure how close. I should go crawl around the bilges and see what were dealing with first, probly

Boat was just recently hauled out for bottom paint and nobody thought to measure the diameter of the tunnel or even look at the blade pitch. No idea what gear ratio on the drive, only that it's a 90 degree box inside the tunnel and maybe there's two props? Actually, the captain should know at least that one. But if they counter-rotate or not? Maybe I'm over-thinking this

I could look at the existing hydraulic motor and see if I can find it's rated RPM and power

Captain just wants to quickie-weld a shaft adapter onto something pulled from a wrecking yard and 'call it good'. Controls are to be simple push-buttons up by the wheel activating solenoid actuators. Full power or bust, I guess. Captain is a retired tugboat operator, so I guess he prefers to power into/away from everything...

Can I get away with having a 500 volt industrial inverter wired up to momentary on, with reversing solenoids after that inverter, all powering a forklift motor? Entire works powered off the existing 24 volt battery banks, of course

I could email Vetus, or somebody, and ask for just the motor & controller on their system. Not sure how well that will work out

Likely we're either just going to install new hydraulics or just keep on going without a bow thruster. But after putting in LED lighting and seeing what's happening out there, captain really wants to have something to brag about that's portray-ably cutting edge. He doesn't like complicated systems, so computerized variable-frequency drives and Star-Trek warp shifters are all totally no-go!

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by amberwolf » Oct 08 2017 3:04am

Some thoughts:

First, is he looking for an improvement on the existing system?

Or just an electric power instead of hydraulic?

If the former, you'll have to find out how much thrust the system presently provides, and find out if it's limited by the hydraulic pressure / power, or if it's limited by how much water can be moved thru the existing ducts and prop.

If the hydraulics are the limit, and increasing prop RPM would increase thrust without causing other problems, then you can use an electric system that forces higher RPMs on the prop. You'd need to know how much power the existing system takes to do what it does, so you can ensure the electric system can do enough more than that to get the RPM you're after to get teh thrust you're after.

If it's limited by the ducts/prop then you'll ahve to replace (or modify) the whole system with something better, and I havent' got any info on that.


Some other considerations:

How many amps can the 24v system provide to the location the thruster will be in?

If it can't provide enough amps, period, you'll have to upgrade the power supply system.

If just the wiring can't handle the amps, you'll have to upgrade the wiring from the thruster location to the power supply system.


If he doesn't want anything complicated, you're down to brushed motors and contactor banks controlled from a button. It'd be on or off, no thrust control. If he needs thrust control you'd have to use a PWM controller for brushed motors.

If you know the power and RPM of the hydraulic system, and RPM increase will do what you want, you can look for big brushed motors from forklifts and such that will handle that power and run at the RPMs you need.

If you can't find a brushed motor that will do those RPMs, then you'll need to gear it up somehow; belt, chain, gearbox, etc. (I suppose if you're gearing it you could also add a multispeed transmission at the same time to give different thrust levels, but that makes it complicated again, and more prone to breakdown if not maintained).

If power levels are low enough, and you need thrust level control, you can use brushed controllers for electric car conversions, like the Zilla, or maybe some of the Curtis or Netgain stuff.


Or you can use a bank of contactors that can carry the current, but if they don't all switch at the same time you can weld them shut and it'll be stuck on until you cut main power somehow. A single contactor to carry lots of current that can also switch that current on and off under load can be expensive, and large.

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by fechter » Oct 08 2017 10:38am

In the ad for the electric thruster, it indicates 9.5hp and 540A @ 24v. That's a lot of amps. If the battery is big enough, it should work. You also need some way to turn it on/off and reverse direction. I'm not sure, but maybe you can get away with a big contactor instead of an actual motor speed control. Just on full blast or off.

Forklift motors and golf car motors are sort of in this ballpark, but many are a higher voltage.

Having a picture of the existing hydraulic motor might be helpful.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by spinningmagnets » Oct 08 2017 11:08am

I would definitely investigate a 48V solution. By upping the voltage, you can cut the amps by quite a bit. This is a vital consideration, because...the lower the amps, you can find components easier, and have a larger selection to choose from.

When you lower the amps, the motor and controller can also be physically smaller, and...as a result, possibly more affordable? A higher-voltage battery pack might be larger and more expensive, but...I suspect the motor is located in a tight spot, and the battery has some flexibility in its location and mounting...

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 08 2017 11:16am

amberwolf wrote:Some thoughts:

First, is he looking for an improvement on the existing system?

Or just an electric power instead of hydraulic?

If the former, you'll have to find out how much thrust the system presently provides, and find out if it's limited by the hydraulic pressure / power, or if it's limited by how much water can be moved thru the existing ducts and prop.

If the hydraulics are the limit, and increasing prop RPM would increase thrust without causing other problems, then you can use an electric system that forces higher RPMs on the prop. You'd need to know how much power the existing system takes to do what it does, so you can ensure the electric system can do enough more than that to get the RPM you're after to get teh thrust you're after.

If it's limited by the ducts/prop then you'll ahve to replace (or modify) the whole system with something better, and I havent' got any info on that.


Some other considerations:

How many amps can the 24v system provide to the location the thruster will be in?

If it can't provide enough amps, period, you'll have to upgrade the power supply system.

If just the wiring can't handle the amps, you'll have to upgrade the wiring from the thruster location to the power supply system.


If he doesn't want anything complicated, you're down to brushed motors and contactor banks controlled from a button. It'd be on or off, no thrust control. If he needs thrust control you'd have to use a PWM controller for brushed motors.

If you know the power and RPM of the hydraulic system, and RPM increase will do what you want, you can look for big brushed motors from forklifts and such that will handle that power and run at the RPMs you need.

If you can't find a brushed motor that will do those RPMs, then you'll need to gear it up somehow; belt, chain, gearbox, etc. (I suppose if you're gearing it you could also add a multispeed transmission at the same time to give different thrust levels, but that makes it complicated again, and more prone to breakdown if not maintained).

If power levels are low enough, and you need thrust level control, you can use brushed controllers for electric car conversions, like the Zilla, or maybe some of the Curtis or Netgain stuff.


Or you can use a bank of contactors that can carry the current, but if they don't all switch at the same time you can weld them shut and it'll be stuck on until you cut main power somehow. A single contactor to carry lots of current that can also switch that current on and off under load can be expensive, and large.
Captain wants electric, just so he can say his ship is more modern. It doesn't need to be more powerful, but if that can be done without adding cost, then maybe

The bow thruster is completely non-functional, and has been that way from the day the ship was first purchased by this captain. So no way to tell how well it works or how much thrust it can achieve

Hadn't even thought of the tunnel & impellers being able to handle more power. Thanks, I'll have to look into that

I don't know how many amps can be drawn off the batteries, I will ask about that next opportunity

At the moment, there's no cabling. So choice of gauge is yet to be determined. I asked the captain if he knows any veterans of diesel subs, for advice on high amperage systems in the bottom of a boat

I'm personally favoring a forklift motor, but I don't yet know how to power a 500 volt motor from a 24 volt battery bank. Just a hazy idea for an inverter that can kick out 500 volts, maybe a diode pack from an arc welder to get some form of DC if the inverter doesn't do that, and really big contactors. I'm looking at how to make contactors, just out of curiosity

But right now I will look at Zilla, Curtis, Netgain - Thanks!

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 08 2017 11:18am

fechter wrote:In the ad for the electric thruster, it indicates 9.5hp and 540A @ 24v. That's a lot of amps. If the battery is big enough, it should work. You also need some way to turn it on/off and reverse direction. I'm not sure, but maybe you can get away with a big contactor instead of an actual motor speed control. Just on full blast or off.

Forklift motors and golf car motors are sort of in this ballpark, but many are a higher voltage.

Having a picture of the existing hydraulic motor might be helpful.
And from what the captain has been asking for, we're looking at twice as many amps!

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 08 2017 11:26am

spinningmagnets wrote:I would definitely investigate a 48V solution. By upping the voltage, you can cut the amps by quite a bit. This is a vital consideration, because...the lower the amps, you can find components easier, and have a larger selection to choose from.

When you lower the amps, the motor and controller can also be physically smaller, and...as a result, possibly more affordable? A higher-voltage battery pack might be larger and more expensive, but...I suspect the motor is located in a tight spot, and the battery has some flexibility in its location and mounting...
Hydraulic motor is in a very tight spot. The boat is narrow - 120 feet long and 18 feet wide

But the same issue for the batteries. There's no place for another bank, and the existing bank is built into it's location. So adding batteries isn't happening. System has to be 24 volts. Maybe we could look into replacing the batteries with higher performing variations, but I expect the budget isn't allowing that. If the batteries were to die a sudden & mysterious death, then we get new batteries...

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by amberwolf » Oct 08 2017 8:18pm

Recursive wrote:I'm personally favoring a forklift motor, but I don't yet know how to power a 500 volt motor from a 24 volt battery bank.
I haven't seen any 500V forklifts, though there might be some newere brushless stuff out there that is.

Most of the brushed motors I've seen from them are are 24V to 48V, just high-current (potentially hundreds of Amps).

I'm looking at how to make contactors, just out of curiosity
They're basically just big relays, but made specifically to switch high currents (and often enough high voltages at the same time) under load, if necessary.

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 08 2017 11:02pm

amberwolf wrote:
Recursive wrote:I'm personally favoring a forklift motor, but I don't yet know how to power a 500 volt motor from a 24 volt battery bank.
I haven't seen any 500V forklifts, though there might be some newere brushless stuff out there that is.

Most of the brushed motors I've seen from them are are 24V to 48V, just high-current (potentially hundreds of Amps).

I'm looking at how to make contactors, just out of curiosity
They're basically just big relays, but made specifically to switch high currents (and often enough high voltages at the same time) under load, if necessary.
I've only this week started looking at what it would take to convert the bow thruster, so it's also the first time I've looked into using forklift motors for any application. When I was looking for 20HP motors, I didn't see any 24 volt forklift motors. But if I change the search to just any forklift motor, then I see lots of 24 volt among other low volt ratings. But I doubt the horsepower is high enough

And today, a friend who is a licensed captain who knows the captain I'm working for and also is familiar with this boat, told me he thinks the bow thruster could handle 40 horsepower. He's fairly certain it's just the hydraulic motor is 20HP. He's seen that size tunnel on other ships

I'm taking another look at the 24 volt forklift motors, maybe we just need to compromise on the amount of power. Because right now we have zero horsepower on this bow thruster. Upgrading to 10HP would be an improvement!

As for making a contactor, maybe that should be another thread. I saw somebody make a type of railgun that fires hard drive platters, so now I'm wondering if that could be a sort of electric piston drive for an air rifle

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by amberwolf » Oct 08 2017 11:54pm

If you look over on DIYElectricCar forums, you'll find a number of car conversions that use "small" forklift motors, sometimes run at higher currents/etc than they were originally used at.

Used to be a guy there (Jim Husted?) that rebuilt them for better operation, but I don't know if he's still around.

Ah, here's a thread by him there; lots of info but it's a couple hundred pages. ;)
http://www.diyelectriccar.com/forums/sh ... -7598.html


Oh, and remember you can use a motor at much higher than it's nameplate rating if you're only doing it for a short period and it can cool off a lot afterward, and/or you cool it externally (like forced air blown thru it during operation).
Last edited by amberwolf on Oct 09 2017 12:07am, edited 1 time in total.

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 09 2017 12:04am

amberwolf wrote:If you look over on DIYElectricCar forums, you'll find a number of car conversions that use "small" forklift motors, sometimes run at higher currents/etc than they were originally used at.

Used to be a guy there (Jim Husted?) that rebuilt them for better operation, but I don't know if he's still around.
As you posted, I was reading this: http://www.diyelectriccar.com/forums/sh ... 598p2.html

Was just googling for anything forklift motor related

DIYElectricCar sticky is making me wonder if maybe I could consider using a 12 volt forklift motor and feed it 24 volts? As a bow thruster, runtime is only a few minutes maximum. Assuming the occasional hard docking maneuver fighting wind or currents

I can add auxiliary cooling. An air blower at the very least

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by fechter » Oct 09 2017 10:07am

A critical item is to match the rpm of motor to the prop. Prop size and pitch will determine the rpm you want. In many cases, some kind of gear reduction will be needed between the motor and prop.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 09 2017 7:13pm

fechter wrote:A critical item is to match the rpm of motor to the prop. Prop size and pitch will determine the rpm you want. In many cases, some kind of gear reduction will be needed between the motor and prop.
Yeah, been asking the captain to schedule a day to look into that, or he can go crawling around in the bilges and look for dataplates. Gearbox will likely remain a mystery as there's no paperwork to show the ratio, and we didn't think of checking that while the boat was hauled out just recently. I would like to be surprised and there's something on the bow thrusters housing to indicate the ratio, but this boat was built in 1893 including this bow thruster

https://en.wikipedia.org/wiki/El_Primero

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by fechter » Oct 10 2017 12:43pm

Amazing history there. Also amazing the thing is still in service after 124 years.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Alan B » Oct 10 2017 1:27pm

Put a motor inverter near the 24V bank, right next to it if possible. This will produce 3 phase AC for the motor at whatever voltage the motor is designed for, perhaps 220V. The motor inverters used for machinery have control parameters for acceleration, deceleration and reversal as well as control inputs, so any 3 phase motor can be used. The high current will only traverse a few inches from the battery to the motor inverter. The run to the motor will be higher voltage and lower current. Hydraulic motors are small, so fitting into the space may be the challenge.

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 11 2017 11:14am

fechter wrote:Amazing history there. Also amazing the thing is still in service after 124 years.
Yeah, it is actually. I see the mess it's in and take it all for granted I suppose. Got lots of little problems and the current owner is not interested in 'doing things right' but instead does everything the cheapest way possible. So all the original nice solid teak & mahogany has to compete with 3-ply B-grade non-marine plywood

But the engines still work, and it's not sinking. This has two diesels run into a single gearbox and just a single propeller. Last month when hauled out, the prop was removed & taken to a specialist to be straightened as the ship was taken into the wrong side of a marina entrance at low tide & hit rocks. The primary through-hull for the main cooling seawater wont close and a pipe fitting on that is leaking. Probably will break if we try to remove it. So until that through hull can be shut, we're stuck with the leak. The gearbox loses oil very quickly and tends to overheat when low. So anytime the bilge pumps run the boat has to be outside the marina so nobody notices the sheen it leaves behind

If you look at that wiki photo carefully, on the breakwater the boat is tied up to, just forward you will see a pair of shadows at the bend in the breakwater(floating concrete dock), those shadows are cast by a pair of steel plates that protect a warning light. But there's now a nice couple of 4 inch deep gouges in the starboard bow on the boat from hitting those. Ship is tied up on the outside of the breakwater because that costs less then being on the inside. That's really why the captain wants the bow thruster fixed, after the fact...

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 11 2017 11:28am

Alan B wrote:Put a motor inverter near the 24V bank, right next to it if possible. This will produce 3 phase AC for the motor at whatever voltage the motor is designed for, perhaps 220V. The motor inverters used for machinery have control parameters for acceleration, deceleration and reversal as well as control inputs, so any 3 phase motor can be used. The high current will only traverse a few inches from the battery to the motor inverter. The run to the motor will be higher voltage and lower current. Hydraulic motors are small, so fitting into the space may be the challenge.
Sounds good! I was hoping there would be an approach like that. But that does put the project into a more expensive category, and veers away from the caveman-simple 'BFH' solution the captain wants

So, any advice on a 10~40 horsepower 3-phase AC controller?

I see some second-hand AC motors on the ebay that should be well inside budget, but it hinges on how pricey the inverter is as well as how simple it can be to setup and get going. It would be good if it doesn't need any computer for settings adjustment. Ramp-up profile only needs to avoid breaking the geardrive, otherwise needs to be as quick as possible. So some sort of industrial default mode that can be set with jumpers would be best. The control input from the bridge needs to be simple relay logic. 24VDC signals coming hot off push-buttons, run through light-weight cabling (phone wire)

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by major » Oct 11 2017 5:26pm

Alan B wrote:Put a motor inverter near the 24V bank, right next to it if possible. This will produce 3 phase AC for the motor at whatever voltage the motor is designed for, perhaps 220V. The motor inverters used for machinery have control parameters for acceleration, deceleration and reversal as well as control inputs, so any 3 phase motor can be used. The high current will only traverse a few inches from the battery to the motor inverter. The run to the motor will be higher voltage and lower current. Hydraulic motors are small, so fitting into the space may be the challenge.
Hi Alan B,

I think you're mistaken about an inverter to run a 220VAC 3-phase motor with 24VDC input. If you know of something like that capable of 15kW, please provide a link. Motor VFD (inverters) for that output will require about 330VDC.

major

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by liveforphysics » Oct 11 2017 6:20pm

Take measurements of the windings resistance and Inductance on the existing bow thruster, and I bet we can find you something that works out.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Alan B » Oct 11 2017 7:34pm

major wrote:
Alan B wrote:Put a motor inverter near the 24V bank, right next to it if possible. This will produce 3 phase AC for the motor at whatever voltage the motor is designed for, perhaps 220V. The motor inverters used for machinery have control parameters for acceleration, deceleration and reversal as well as control inputs, so any 3 phase motor can be used. The high current will only traverse a few inches from the battery to the motor inverter. The run to the motor will be higher voltage and lower current. Hydraulic motors are small, so fitting into the space may be the challenge.
Hi Alan B,

I think you're mistaken about an inverter to run a 220VAC 3-phase motor with 24VDC input. If you know of something like that capable of 15kW, please provide a link. Motor VFD (inverters) for that output will require about 330VDC.

major
You may be right, I'm not too familiar with that particular product market. I have a 24V to 3kW inverter that can be connected in parallel up to 10 units, and 20 more combined into 3 phase for a total of up to 30 units and 90kW, but I suspect that it would require several separate 24V battery banks to be operated to keep the cabling at reasonable current levels. The cost is about 50 cents per watt, so that's not cheap either.

Can your 24V battery bank actually deliver 625 amps safely with reasonable voltage sag? Have you looked at that cabling? The cost of cable alone may break the budget.

Modern ships do use all-electric drive systems, so clearly they exist, but I doubt they are cheap. They use diesel generators, not batteries to provide AC power, as far as I know.

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 12 2017 1:21am

major wrote:
Alan B wrote:Put a motor inverter near the 24V bank, right next to it if possible. This will produce 3 phase AC for the motor at whatever voltage the motor is designed for, perhaps 220V. The motor inverters used for machinery have control parameters for acceleration, deceleration and reversal as well as control inputs, so any 3 phase motor can be used. The high current will only traverse a few inches from the battery to the motor inverter. The run to the motor will be higher voltage and lower current. Hydraulic motors are small, so fitting into the space may be the challenge.
Hi Alan B,

I think you're mistaken about an inverter to run a 220VAC 3-phase motor with 24VDC input. If you know of something like that capable of 15kW, please provide a link. Motor VFD (inverters) for that output will require about 330VDC.

major
Darn, really want to see this link...

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 12 2017 1:23am

liveforphysics wrote:Take measurements of the windings resistance and Inductance on the existing bow thruster, and I bet we can find you something that works out.
Uhm, hydraulic motor?

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 12 2017 3:04am

Been seeing a few references of Curtis controllers being able to run off 24volts. So I dug up this: http://curtisinstruments.com/Uploads/Da ... _RevC3.pdf

1238E-48XX looks like a something: 24~36 volts nominal/800 amps for 2-minutes

But I'm not limiting myself to AC motors. I'd look at what else they have, but maybe tomorrow

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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by fechter » Oct 12 2017 9:00am

I searched around a bit and did see some AC forklift motors. These are not cheap, and most of them have some kind of splined output shaft which may be difficult to adapt. There are quite a few old-school brushed forklift motors and these tend to be less expensive but may not hold up well in the long run in a marine environment. Whether AC or DC, it will be hard to find something that's really 20hp. Closer to 10hp might be a more practical target.

Any idea how big the batteries are? They will need to be very large to support this kind of draw for more than a few seconds.

Here's another crazy idea. Not sure if this could really work. Instead of running off the batteries, see if there is a way to install a generator (or alternator) powered by the diesel engine. It would need to be about the same physical size as the thruster motor. No controller, just a massive contactor to reverse direction and turn off. This way you won't be messing with the 24v system on the boat. You would need garden hose sized welding cables to run from thruster to diesel. With a separately excited brushed motor, you might get away with no contactor and only need to control the field winding, which is much lower current.
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Re: 20HP Bow Thruster, 24VDC Battery Bank

Post by Recursive » Oct 12 2017 12:44pm

fechter wrote:I searched around a bit and did see some AC forklift motors. These are not cheap, and most of them have some kind of splined output shaft which may be difficult to adapt. There are quite a few old-school brushed forklift motors and these tend to be less expensive but may not hold up well in the long run in a marine environment. Whether AC or DC, it will be hard to find something that's really 20hp. Closer to 10hp might be a more practical target.

Any idea how big the batteries are? They will need to be very large to support this kind of draw for more than a few seconds.

Here's another crazy idea. Not sure if this could really work. Instead of running off the batteries, see if there is a way to install a generator (or alternator) powered by the diesel engine. It would need to be about the same physical size as the thruster motor. No controller, just a massive contactor to reverse direction and turn off. This way you won't be messing with the 24v system on the boat. You would need garden hose sized welding cables to run from thruster to diesel. With a separately excited brushed motor, you might get away with no contactor and only need to control the field winding, which is much lower current.
Not such a crazy idea, it's like a diesel/electric locomotive. Boat has a pair of 440 3-phase gensets, each about 70HP. Only one is used at a time to charge the batteries and to run the anchor winch

I'm already thinking about doing exactly this, just got to find a reversible 440 3-phase motor

Anchor winch uses a reversing gear to let the chain out. Could have been just a clutch with a brake, but it's a nicer setup. It's motor doesn't reverse though

Which reminds me of a totally different train of thought. In a category of how to make a ICE-powered vehicle better in it's own right. Just recently, I read about a prototype Peugeot that took a pair of planetary gearsets, joined them together so that without any outside influence a rotation of the input would not pass through to the output. This is because the 1st planetary gearset did not anchor it's outer ring but instead used that to drive the 2nd gearset. Meanwhile the planetary ring is used as usual to drive the other input of the 2nd gearset. The two sets would spin against each other in a constant slipping mode. Where it gets interesting is in how the outer rings are connected, because a 1:1 ratio at this point results in zero output of the combined gearbox. But a way to change this ratio on the fly forces the 2nd gearset to begin providing power at the transmission output

The method used by Peugeot is to use the 1st outer ring gear to power a 3-phase AC generator, run that to an inverter, and then use the inverters output to drive a matching 3-phase AC motor attached to the 2nd gearset

The ECU in charge of shift control, would alter the inverter output to change effective ratio. The amount of torque being transferred electrically is much lower than what is transferred through the gears. Somewhat like controlling the field winding current of a DC brushed motor to regulate RPM

And so, I have high-jacked my own thread!

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