4 Wire servo motor

hi, i had some experience with 3 wire servo mototr controlled with arduino..is so easy.... i got a 4 wire servo motor with continuous rotation, if i attach the +24 and GND wire...it start to spindel, i was wondering if there is any possibility to control the 4 wire servo with some l292d and pwm for the positioning just like the 3 wire servo...i have searched in the internet about the datasheet of the motor, but i got nothing.... someone has an idea?

the motor is a DMES8G-03... there is also some kind of electroninc circuit attached... there is no info in the internet about it...

Isn't that a stepper motor ?

no... on the side of the motor there is "DC 24V Servo Motor"... also a stepper doesn't make continiuos rotation if i attach 2 wire... i said if i attach the +V and GND it make continuous rotation just like a dc motor...

If it is this one:


The extra wire is some kind of magnetic pickup

yes that is... i have seen that post before,... but what is a magnetic pickup?... is there possible to control it just like a regular 3 wire servo motor with arduino?

Adizhavo, Can I come in here with a similar question about 4 wire servos. I want to use some from an old (1970's) Swan Radio Control outfit. There are red, white, black and yellow wires. What do I need to connect to what to get them to work? Regards Mick

rookesy...i started to control the 4 wire servo just like a normal dc motor... i connected the phase wire (red) to +V and grounded the black wire..it started to spindel clockwise, you can control it easy with L292D or H-bridge transistors (clockwise and counterclockwise), you can divide the inputs in small delay with the arduino (maybe 10 milliseconds) and control the position by counting it.... but what i am asking is if it can be control as a servo and not like a dc motor...the servo has more torque since it always want to remain to that degree, that's why i have open this topic...........or maybe we can both apply some gear reduction or gear system..but that is another thing

the servo has more torque

That is generally because of the gearing, take a look at the inside of a rc servo:


So, apart from the gearing (that in the end are connected to a potentiometer), you also need some electrtonics that translate the servo signal from your arduino, to something that can contol the motor/potentiometer

This topic is really old, but I think I found another post here that explains the best way to control it. Essentially you apply a DC voltage between the + and - leads to move the motor in what ever direction you want, and read the pot with the other two leads. You can't control it with the servo library.