Ibnfshn?

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10-23-2008, 06:05 PM
Cane Pole

Ibnfshn?

Bill,

Do you have a trolling motor stall current guide?

I found a couple of cheap pwm circuits on ebay. Cheaper to buy one than build now days.

I got a 37 lb Motorguide on my Jon boat with 5 speeds. I can hardly turn the know anymore. Old age sucks.

I could stall the motor and find out but I do not have a current clamp.

These speed controllers will handle about any tm.

The show 30/60/100 amp controllers. 12 to 40 volts. Hard to beat the prices. Made in China......American technology.

These would be easy to implement as a speed control.

Thanks,

Tom

dc motor speed controller, Business Industrial, Electronics items on eBay.com
10-23-2008, 06:43 PM
Barnacle Bill

Quote:

Originally Posted by Cane Pole

Bill,

Do you have a trolling motor stall current guide?

I found a couple of cheap pwm circuits on ebay. Cheaper to buy one than build now days.

I got a 37 lb Motorguide on my Jon boat with 5 speeds. I can hardly turn the know anymore. Old age sucks.

I could stall the motor and find out but I do not have a current clamp.

These speed controllers will handle about any tm.

The show 30/60/100 amp controllers. 12 to 40 volts. Hard to beat the prices. Made in China......American technology.

These would be easy to implement as a speed control.

Thanks,

Tom

dc motor speed controller, Business Industrial, Electronics items on eBay.com

I thought only robot builders were concerned with stall current? Whoops, wait a minute, you are one. :D I've never seen that listed anywhere for trolling motors. They don't even give you max current draw any more when buying a new motor. My MK repair manual doesn't have anything either.
10-23-2008, 06:58 PM
PanMan_VA

I emailed a local TM repair shop to see if they know the typical stall current for both 12v and 24V TMs. I'll post the answer here if I get one.

Most of the information I've seen has the max operating current of 12v and 24v TMs at around 45 amps.

I'm more of a mechanical systems/system engineering guy so my understanding of electronics is sometimes limited. I start to get lost with complicated ICs and FPGAs. Wouldn't a 50 amp breaker trip before the 100 amp PWM controller was damaged?
10-23-2008, 08:21 PM
Barnacle Bill

Quote:

Originally Posted by PanMan_VA

I emailed a local TM repair shop to see if they know the typical stall current for both 12v and 24V TMs. I'll post the answer here if I get one.

Most of the information I've seen has the max operating current of 12v and 24v TMs at around 45 amps.

I'm more of a mechanical systems/system engineering guy so my understanding of electronics is sometimes limited. Wouldn't a 50 amp breaker trip before the 100 amp PWM controller was damaged?

I don't think a normal breaker would react fast enough. But Tom would be the expert on that.
10-23-2008, 10:20 PM
Cane Pole

Found this MG table.......

Looks like the 40 lb TM max current is 20 amp. The stall current is less than 30 amp, as the fuse don't blow when I momentarily stall the motor.

I did a little calcuating.

40 lb 12v = 250 watt motor = 20 amp max continuous. or .335hp

70 lb 24v= 480 watt = 20 max draw continuous. or .643hp

These numbers are kinda what I imagined as I do not blow a 30 amp fuse when I stall either motor.

I would guess that the minn kota motors are similar in watt rating for the same thrust.

It is hard to relate thrust to power as there is no direct correlation of the two.

I believe the 30 amp controller will work as it has short circuit protection @35 amps. Fuse should blow if a short in the motor occurs.

attatched is a MG service chart.
10-23-2008, 10:31 PM
Wiskers

Speek English

Ok... I tried to read these posts. What language is the thread in? :D:D:D
10-23-2008, 10:47 PM
Cane Pole

Quote:

Originally Posted by IBNFSHN

I don't think a normal breaker would react fast enough. But Tom would be the expert on that.

Fets blow in microseconds. Fuses blow in milliseconds. They are both gay.:p:p
10-24-2008, 09:03 AM
flycaster

Quote:

Originally Posted by Cane Pole

Fets blow in microseconds. Fuses blow in milliseconds. They are both gay.:p:p

If you take out the queer electrons this won't happen.:):):eek::eek::eek:
10-24-2008, 09:19 AM
Wiskers

Quote:

Originally Posted by flycaster

If you take out the queer electrons this won't happen.:):):eek::eek::eek:

Now I'm really confused! :confused:
10-24-2008, 09:34 AM
akmoose40

wiskers........

Quote:

Originally Posted by Wiskers

Ok... I tried to read these posts. What language is the thread in? :D:D:D

wiskers, i belive those two are related to alan greenspan the ex fed chairman......no one could understand his greenspanesse either.....
10-24-2008, 09:41 AM
CrappieHound

Funny!

The Hound
10-24-2008, 10:15 AM
frank lawhead

They just talk like that to make me fell stupid---:):)
10-24-2008, 11:25 AM
Cane Pole

Hey Bill

Here are some calculations that I did with the MG info. MY figures are based on the MG chart and are only as accurate the MG chart. This info might be added to one of your stickies..Good poop here......for those interested.

The model is the advertised thrust. Minn Kota numbers should be close based on thrust. You know they want ever tell us the facts.

Motoguide recommends a 50 amp manual reset breaker and 6 gage wires for needed wiring that exceeds the wire that comes with the unit. It is just a CYA recommendation. I don't fault them though.

Someone might want to check my math. My hands shake like a dog passing peach seeds sometimes.:(:(

Tom

http://i188.photobucket.com/albums/z...iring/MG-1.jpg
10-24-2008, 11:33 AM
Barnacle Bill

Quote:

Originally Posted by Cane Pole

Here are some calculations that I did with the MG info. MY figures are based on the MG chart and are only as accurate the MG chart. This info might be added to one of your stickies..Good poop here......for those interested.

The model is the advertised thrust. Minn Kota numbers should be close based on thrust. You know they want ever tell us the facts.

Motoguide recommends a 50 amp manual reset breaker and 6 gage wires for needed wiring that exceeds the wire that comes with the unit. It is just a CYA recommendation. I don't fault them though.

Someone might want to check my math. My hands shake like a dog passing peach seeds sometimes.:(:(

Tom

http://i188.photobucket.com/albums/z.../wiring/MG.jpg

Are these figures based on the motor running at max? If so it sorta makes me think when you call them for max current they are giving you stall current. Probably like you said, its a CYA deal.
10-24-2008, 12:06 PM
Cane Pole

Quote:

Originally Posted by IBNFSHN

Are these figures based on the motor running at max? If so it sorta makes me think when you call them for max current they are giving you stall current. Probably like you said, its a CYA deal.

My figures are based on the KW rating of the motor. That should be max current before stall. All the small motors (1/100 hp, etc) I work with usually provide the stall current. I built my drive circuit based on the stall current. Cant get anything from either Minn Kota or Motorguide.

Do you remember when everything used to come with schematics and specs? What happened? Paranoia musta hit the market place I guess.

I had to correct my drawing already. sad.......
10-24-2008, 01:48 PM
Cane Pole

Just got off the phone with Motorguide tech. He told me that 42 amp is the stall current on all MG troll motors. Another CYA number. He agreed and laughed.

Of course he could not recommend anything except purchase a new digital TM. However, on the side, he said I was on the right track though and again laughed.

I asked why MG don't sell the add-ons pwms. He said it was more money in selling new TMs than "enhancing the old ones. At least he was honest...:rolleyes:

Looks like a limited market product item to me. Upgrade a 100 dollar tm with a 100 dollar product enhancement add on. Yep.......
10-24-2008, 08:04 PM
PanMan_VA

I got an answer from the local TM repair shop

"Please contact Minn Kota direct at 1-800-227-6433."
10-24-2008, 08:32 PM
Cane Pole

Quote:

Originally Posted by PanMan_VA

"Please contact Minn Kota direct at 1-800-227-6433."

HAHA...Amazing.......

I believe you can use the numbers in the chart I posted with some tincy faith. The Motorguide rep was really candid. Well, I thought so anyway.

The thrust vs hp ratings should be comparable. Both MG and MK are just compound wound dc motors producing equivalent thrust at a fixed voltage. Not to much secret there.

Tom
10-25-2008, 01:23 PM
Cane Pole

tm speed controller

I pretty well much settled on this controller by 4qd. I have used their products in the past. good stuff. I am waiting on technical response from the Britts.

http://www.robotcombat.com/products/4QD-Uni-4-12.html
12-29-2008, 02:39 PM
wasabi

well, canepole, did you follow through and do this or not? I'm sitting here googling 12v pwm's thinking about doing the same thing. Surprised to see my 40 lb. thrust motor is only pulling ~20 amps, but that just lets me buy a less expensive PWM. I seen the ones on eBay, haven't bought one yet. Getting one means I have to mount it in a box, waterproof it, etc.
12-29-2008, 05:15 PM
CatFan

I think stall current is figured from a DC resistance reading of the motor coil. I don't know how the speed coil would affect that reading, but I'd assume if you measure with the switch set on 5 you see only the winding. You might call or email John Jones at jonestrollingmotor.com He's a member here, but doesn't visit too often. He's a good guy and can answer your questions.
12-29-2008, 05:59 PM
Cane Pole

Quote:

Originally Posted by CatFan

I think stall current is figured from a DC resistance reading of the motor coil. I don't know how the speed coil would affect that reading, but I'd assume if you measure with the switch set on 5 you see only the winding. You might call or email John Jones at jonestrollingmotor.com He's a member here, but doesn't visit too often. He's a good guy and can answer your questions.

This is the proper way to really do the measurements. My meter is not very accurate (poor) in the sub ohm readings ranges.
12-29-2008, 06:01 PM
Barnacle Bill

If you call any of the TM makers and ask for max amps any motor will pull they will give you the stall current rating. You need this to properly fuse the circuit.
12-30-2008, 08:20 PM
Ferdi

OK, I've tried to read this post, where is the "PRESS ONE FOR ENGLISH VERSION"????? Ferdi aka Fred PS Happy New Year to all.....
12-30-2008, 09:57 PM
Barnacle Bill

Quote:

Originally Posted by Ferdi

OK, I've tried to read this post, where is the "PRESS ONE FOR ENGLISH VERSION"????? Ferdi aka Fred PS Happy New Year to all.....

Lets see if I can clear it up a little for you. Say you were running down the creek wide open with your 55 lb thrust MK. Also you happen to have an amp meter installed on it. At full speed the amp meter should be reading somewhere around 20 amps. All of a sudden you run into a plastic bag and the prop comes to a screeching halt. The amp meter is going to run up to 42 amps very fast. This is the stall current. Although the motor only draws 20 amps normally you still need a 50 amp fuse or breaker or else everythime you ran into some weeds you would blow it. You can calculate the stall amps if you know the resistance of the armature and apply ohm's law. Hope that makes sense.
12-31-2008, 11:32 AM
wasabi

Bill (canepole too) - any thoughts to the comment I posted? Did canepole ever build/install a PWM for this motor?
12-31-2008, 12:05 PM
Cane Pole

Quote:

Originally Posted by wasabi

Bill (canepole too) - any thoughts to the comment I posted? Did canepole ever build/install a PWM for this motor?

Too cold to work on a boat. I am working on my robot right now for the robot races in March. I am using front wheel drive, front wheel articulated steer, and an articulated body. Presently, I am writing the program code to control this thing. The code is the easy part. I have problems with the mechanics. I read a lot on steering, the I go SWAG...This keeps me off the streets.

I ain't got a boat yet. I am looking fer one. I will get a roundtuit.

The pwm circuit has to be able to source the stall current without blowing up. You let the smoke outa these things, they quit working for some reason....