Starter moter

[jamesb]

Starter moter

people assume there is only one type of starter motor on the planet. 4kg??? nope.

In case our friend hasnt read the links above, basically, you have to open the motor, disconnect almost everything, all armature brush wires and the feild coil wires, then take them all outside of the motor. Then you have the wonderful job of wiring them, which is a little tricky, especially at 3am when rushing for an event.

I havent bothered. It runs one way only, as the motors Ive rewired in the past havent been that great as drive motors. If you are considering them, Id say for weapons only. just a personal view though.

[jim]

Starter moter

Is this still true for permanent magnet starter motors? I would have thought these would run in either direction without modification.

You still have to isolate the motor case from the chassis, though.

[jamesb]

Starter moter

true, there was me thinking there was only one type of starter motor on the planet too.

never used one myself, but yep, theres lots of ways and means.

[big_nipper]

Starter moter

Current limiting any motor will always reduce the power it can deliver if it hits that limit. It does however conserve batter power and prevent damage to the motor and controller. The problem is most starter motors have very low resistance and when starting act like a short circuit. Without a really good current limit (for PWM controllers it needs cycle-by-cycle limiting for best performace) it will damage the MOSFETS over time. We only use 4.8Ah for our two 800W motors with a 70A limit and we have never run out of power in a 5 minute fight.

There are of course more than one type of start motor. But in general the ones Ive seen are usually alot heavier than other motors for the same power output and require big batteries. James, looking at your other robots if you say it will work then Im sure it will and I look forward to seeing it in action.

[Guest]

Starter moter

i did read the link it told me a lot but it did not ancer the question about the gear sliding on the shaft or the whole shaft sliding and limiting the curent is out of the question im tying to build on a very low budgit so is there any other motors that will work that i can pickup at a scrap yard thaks for the help one of you said wiper motors are good and you can wiper motors at a scrap yard to right thanks for the help

[blazerbotics]

Starter moter

wiper motors are best for featherweights. if your looking at bulding a heavy, then wheelchair motors would be the easiest to get hold of on a scrapyard (we got ours from there). they may also have the control gear as well, which can be easily modified.

[Guest]

Starter moter

Theres a special chapter on that page called http://homepages.which.net/~paul.hil.../Starters.html

[mightymouse]

Starter moter

I used starter motors for the drive power in Velocirippa for 2 years and actually qualified for series 3&4
with them. They had tremendous torque at only 12v but the current draw was horrendous. In combat I
would often find cables stripped of insulation or even melted together, and lots of puddles of solder.

Reversing was pretty straight forward with heavy duty relays, but speed control came from switching from
6v to 12v batteries (2 speed). It was almost impossible to make the batteries last 5 minutes, if they did they
were totally flat, so I had a car full of charged spares.

I finally bought 2 littons but to match the torque output of one 12v starter I have to push 36v through both
motors.

That said I would not touch them again ever, even as a weapon drive. I now have reliability, batteries that
will go 3 or 4 fights without charging, speed control, and smaller cables. I also don€™t have a box full of
melted relays.

If you are working to a budget I would recommend scouring the scrapyards for air-conditioning fan
motors from audi or VW€™s, some of these use 12v Bosch motors and are pretty powerful, I know, I have
one that was given to me by a friend and it only cost him a tenner. Visually they are identical to the 24v
Bosch motors used by many builders.

[kinforester]

Starter moter

Also dont for get the radiator fan motors ,some of them are quite big ,i got some bosch motors very similar to the 750 GPA a while back.

GORD

[woody]

Starter moter

So David the recommendation of seasoned Roboteers is .... Leave starter motors alone!

[Guest]

Starter moter

[Post removed by admin]

Please be advised that profanity is not acceptable and repeated use will result in the deleting of your user account.

FRA forum admin team

[Guest]

Starter moter

Christian has been helpful in providing a link to one of the best resources for this sort of thing on the web. The fact that you have not read it (you cant have, or youd have the answers to most of your questions) does not give you the excuse to address other people in that manner.

I could provide you with quite a few in depth link describing the relative merits or using wheelchair motors, but you are really not deserving of the time that people have gone to to try and help you.

Suggest we have some moderator attention in this thread before we end up with the second pointless flame war of the week.

[spinnerboy]

Starter moter

Yupo swearing like that is a big no no and i will not be suprised if admin ban his account.

[Guest]

Starter moter

I was trying to help you, but the fact that you didnt read the link is quite obvious, it would have answered most of your questions (including that about the solenoid).

But as Im not easily offended, I will still try to answer your questions. You may also want to look at the Reliance motors from Roger Plant. They may not be the best motors in the world, but theyre fairly cheap and have moderate power.

The choice of wheelchair motors is huge. They can produce anything from 300W to about one horsepower. But most importantly, they already have gearing.

The radiator fan motor in most cars will produce something like 400W if theyre run at their recomended voltage (four times that if you double the voltage). Theyre also quite cheap and might be a good choice.

If you decide to go for them, try finding the motors from an old Audi 100 (they weigh about a kilo more, but peak at about 600W instead).

[Guest]

Starter moter

but i did read the link it said 2 difrent things about the seanoid i couldent tell what it was trying to tell me that i moved the shaft or the gear thaks for the help with the wheel cair motor and the radiator fan motors sory about the last post i had a bad day