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From: "Da Man"
Subject: Re: EMI and DC motors
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
Date: Fri, 03 Jan 2003 07:04:59 GMT
NNTP-Posting-Date: Fri, 03 Jan 2003 03:04:59 AST
Did you look at zero cross switching?
Or if your switching by the phase angle, introduce some slew into the power
switches to minimize HF generation.
"PDRUNEN" wrote in message
> Hi Group,
> I am driving a 120V DC motor with a chopped 120V 60Hz full-wave to control
> power (speed) of the motor.
> To remove EMI at the high frequenices, i.e. 400 MHz, the motor
> 50uH chokes in each leg of the motor power input and the input is is
> as well. The average current of the motor is about 3 amps.
> The 50uH chokes are made using Ferrite material. I have been told that
> of the current (3 amps) the Ferrite material (the choke is small size) is
> salurated and the 50uH is most likely 1uH or less at 400MHz and we should
> used iron-core material instead.
> Would ask the group for comments about the Ferrite material saluration and
> other areas to help reduce emi with DC motors.
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