# For motors expertes

Discussion in 'The Projects Forum' started by tracker, Jun 2, 2011.

1. ### tracker Thread Starter Member

Jun 1, 2011
41
1
HELLO
i'm posting here for giving me a method to calculate the ''''RATED CURRENT FOR MY STEPPER MOTOR[/U][/B]'''' here some informations--->

SANYO DENKI COMPANY
TYPE:103H548-0741 (the datasheet is impossible to found).
1.3Ω ________________1.8°/STEP.
6 WIRES STEPPER MOTOR.

my teacher said to me that it's hard to determine it because the construcor is the only one who can. is that true???

i'm looking forward to hear from all of you

2. ### SgtWookie Expert

Jul 17, 2007
22,183
1,729
Here is the Sanyo Denki America contact page:
http://www.sanyo-denki.com/contact.aspx

Why don't you write them via that page, and include the information that you posted, and ask them if they can give you the specifications for the motor, preferably in a datasheet?

3. ### tracker Thread Starter Member

Jun 1, 2011
41
1
Yes it's a solution jut for curiosity how can a man calculate it?

4. ### SgtWookie Expert

Jul 17, 2007
22,183
1,729
If you don't have the current or wattage or VA specification for the motor, you will have to test the motor. You can't calculate it without knowing how the motor is made. If you take the motor apart to see how it is made, it will be ruined.

If you give it too much current, you will burn it up.

It is much easier to get the information from the manufacturer.

5. ### THE_RB AAC Fanatic!

Feb 11, 2008
5,435
1,305
Sorry to differ SgtWookie but you can usually determine motor V and I specs from the resistance, and the package type and size. This is because the coil dissipation is rated by package size and remains quite constant at X watts per phase for that size and type of motor.

Tracker, if you find a same sized and appearance Sanyo Denki motor which shows how many watts (or Volts and Amps) per phase, you can use that as a guideline which should be very close to your motor watts/phase.

For instance most Sanyo Denki size 23 motors I have here are about 5W to 7W per phase, so you get one rated at 5v 1A (ie 5W) and another is 12v 0.4A (about 5W) etc.

Since the package tells you P (Watts), you can get V and I from measuring winding resistance in ohms and these calcs;
V = squareroot(P * ohms)
I = V/ohms