Brushed motor terminology

[bwells]

I understand the size of a motor is dictated by the first number, 380, 540, 700, 820. I assume that number is the can size, not sure what the other two are for as it is not number of turns which would be real handy. I recently purchased a Cordite 820 motor solely to see the size as I have a OSE 700 SC and expected this 820 to be a Yugo starter motor. It is exactly the same size and in every angle, the same motor as the OSE 700. The number of turns seems to be important but once you take it out of the box, it's lost. My question is, what is the difference between the 820 verses the 700. It sure would be nice if these motors were designated as say 721, meaning 700 series with 21 turns, 820 8 series with 20 turns, 540, 5 series with 40 turns, ( that would be a windshield wiper motor). Any clarification would be appreciated and info on the Cordite thing would be better! Brian

[bwells]

bump. Bad timing on my part. Still wondering!

[marker]

Brian
I assume that it is a rebadged Graupner 820 that has a can length of 68 mm and dia of 48 mm, compared to the 700 's can length of 67 mm and dia 44 mm.
The Graupner specs are here.

http://shop.graupner.de/webuerp/servlet/AI?ARTN=6375

Mark

[bwells]

Wow, Thanks and I would not know the diff without miking it but what is the difference between the 820 and the 700. So I may have a Graupner which is a good thing. Does anyone know the number of turns on either motor? There should be a standard to identify the size and turns period>

[bwells]

No, that appears to be a different motor. Is there a way to figure out the number of turns when you don't have the box it came in? It would be nice if the motors were stamped.

[Ub Hauled]

I believe that the SC700 is a 13turn motor... one of the few good race legal 700's out there...

[domwilson]

Found this page on Graupner Motor specs... http://www.slkelectronics.com/ecalc/graupner.htm

[bwells]

UB: 13 turns would need a gear drive wouldn't it? OSE says it can handle a bigger prop so I was thinking in the 20 + turn range. I guess I will GPS the two motors and see who wins. I just wish the 700 and 820 had some reason for being called that.
Dom: did you see anything in that chart that would apply? The 820 specs looks as though this is an antenea (sp) motor (1200 rpm/v). The 700 appears to do 2000 rpm/v which I surely do not hear when running. Thanks

[domwilson]

UB: 13 turns would need a gear drive wouldn't it? OSE says it can handle a bigger prop so I was thinking in the 20 + turn range. I guess I will GPS the two motors and see who wins. I just wish the 700 and 820 had some reason for being called that.
Dom: did you see anything in that chart that would apply? The 820 specs looks as though this is an antenea (sp) motor (1200 rpm/v). The 700 appears to do 2000 rpm/v which I surely do not hear when running. Thanks

Some of them only do 770 rpm/v. From what I remember in the past, a lot of these motors are rebadged Mabuchi or Johnson motors. You may want to take a look at their sites. Here is the site for the Mabuchi motors. http://www.mabuchi-motor.co.jp/cgi-bin/search/e_use.cgi The 700 series are under RS-755WC (Drill and screwdriver)

[marker]

The 700SC is a 10 turn motor in fact 10 turns of 0.95mm wire .
It's Kv is 1550 I've measured all of these specs.
The 700SC also has Neo magnets
The 700 is a Mabuchi motor and I believe the 820 is a Johnson motor.
You really can't compare these two motors by how many turns they are, you need to use their kv and how many amps they can draw as that determines the torque of the motor.

http://www.johnsonmotor.com/PMDC-Motor.384.0.html

http://www.mabuchi-motor.co.jp/en_US/technic/t_0302.html

Mark

[bwells]

Mark: I am under the impression that the lower the number of turns, the higher the RPM but lower torque. Apparently too basic but this is a learning thing and I welcome all info. I have no way to check amp draw so I will do a motor switch with GPS and figure out from there. The ten turn thing blows me away though. Thanks for your info, It gives me more things to think about. Brian