Recovery diodes

K

krunal_299

New Member

• Oct 23, 2007

• #1

Hi!
What kind of diodes should be preferred to eliminate back voltage accross the motor windings?
Will 1n4148 do the job or 1n4001 is better?

 

dknguyen

Well-Known Member

Most Helpful Member

• Oct 23, 2007

• #2

YOu want a diode that is can turn on and off fast (so called recovery time) and is low forward voltage. Such as a schotky diode.

Between the two you listed, the 1N4001 is too slow (it's a regular diode). You need the 1n4148 (it's a high speed switching diode). It's still slower than a schotky though and has a forward voltage. THe diodes of this series are cheaper though than schottky diodes and have less reverse leakage current (but who cares since you got something pulling motor sized currents).

 

Last edited: Oct 23, 2007

Eplanet

New Member

• Oct 24, 2007

• #3

hello krunal_299
for this issue you should see that what Amper getting your motor؟
for example if your transducer getting under 1Amper you an use 1N4148 and if your transducer getting above 1Amper you can use 1N4001.
good lock
Eplanet

 

Last edited: Oct 24, 2007

Sceadwian

Banned

• Oct 24, 2007

• #4

In motor applications the leakage of a Schottky is a non-issue. You have to determine the amount of energy that the back EMF pulse will generate and value your Schottky appropriately though. Low power (bellow 1 amp) Schottky's have absurdly low voltage drop and virtually no recovery time. I'm not sure if it's a typo or not (it was an expensive device though) but I saw a 1 amp Schottky in a Digikey catalog that had a voltage drop of .06 volts.

 

M

mneary

New Member

• Oct 24, 2007

• #5

Previous responses are only guesses because you have not provided sufficient information. We need the operating current and voltage of the motor, and if possible the leakage inductance of the windings. We're fairly confident that you're asking about a DC motor.

There are very few motors where a 1N4148 (100 mA) is suitable, and also few applications where a Schottky is necessary.

1N4004 is usually a good fit up to 150VDC and 1A.

 

Last edited: Oct 24, 2007

RODALCO

Well-Known Member

• Oct 24, 2007

• #6

I would even go for a 1N4007 which is rated at 1000 Volts and cost the same as a 1N4004. also 1 Amp rated.

Otherwise go for a 1 N5408 which is 1 kV and 3 Ampères.

 

K

krunal_299

New Member

• Oct 24, 2007

• #7

Thanks every one here!
That is for Stepper motor of 1amp, 6,5volt rating with l298 driver.
One more thing to MNEARy:
As per my documentation, 1N4148 has 300mA rating. So pls let me know if i am lacking sonewhere!
All regards!

 

Last edited: Oct 25, 2007

ericgibbs

Well-Known Member

Most Helpful Member

• Oct 25, 2007

• #8

I would use 1N4001 diodes.

 

M

mneary

New Member

• Oct 25, 2007

• #9

Some vendors (e.g. Fairchild) only rate 1N4148 at 200 mA.

Since the forward drop increases as you approach the rating, I tend to derate them (especially since the 1N4004 is cheap).

 

Hero999

Banned

• Oct 26, 2007

• #10

Don't worry about the continious rating, it's the peak reating thats important.

A 1A diode might be able to stand 50A for 20ms so if you're driving a 10A motor there's no need to de-rate it.