Schottky Diode

[RCFlyer55]

I need to find some Schottky Diodes for a motor. I have looked in Radio Shack and can not find them. Care they called anything else by chance? What size would I use for a 400 size can motor(brushed)?

[KillerWatt]

Since it seems to have something to do with handling the motor's normal "counter EMF" voltage kick, which some counter EMF's can be up to 10 times higher (but opposite polarity, thus the "counter") than the applied battery voltage.......a voltage rating of > 100 vdc seems important.....don't know about the current rating needs as the duty cycle could be short........ kw

[MAVA]

Go to a "Ma and Pa" electronic store.. If one is not available?

Call on one who carrys the Diodes or the NTE product line(there are serveral dozen types) in the catalog.

The NTE line is available online. here is the link..http://www.nteinc.com/

Select Product selector

Semiconductors

Schottky diode

For Speed 400 and Speed 600 I use a 5A with axial leads and solder it to the motor.

For the Larger Brushed motors I use the 20A in a TO-220 Package(The plastic package with a metal tab with a hole in it)

Most speed controllers omit them because the Power fets contain them.....well...yes they do, but the power fet fails because the one on the FET s not as robust as external Schottky Diode.

Nothing wrong with adding a Schottky diode to a brushed motor.

Just remember the the Banded side of the diode(the Cathode) goes to the positive output lead of the speedcontroller and the other lead goes to the negative output lead.

You can put one on the input of the speed controller also? It will protect it from a reverse polarity connection...

Hope this Helps

Martin

[vintage1]

I am using 5A 50v types on 3sLIPO with no ill effects.

IR somethig or other.
I got a batch off Ebay.

Worth a check,

[RCFlyer55]

I found 2 at "Mousers" which would be best?

Diodes Inc. Rectifier - Schottky SMC 60V 5A

OR

Diodes Inc. Rectifier - Schottky POWERMITE3 60V 5A

ALso I need to buy more capacitors. I know I need 0.047uf Ceramic Capacitors but there are TONS out there. Which would work best?

Kemet Molded Radial Ceramic Capacitors 50V 0.047uF 10%

Kemet Conformally Coated Axial Ceramic Capacitors 50V 0.047uF 10%

Kemet Conformally Coated Radial Ceramic Capacitors 50V Z5U 0.047uF 20%

I got over 500 different types when I searched Mouser.

[e-sailpilot86]

Are you in CA? If you are, go to halted computer supply. They're online too. Sorry, can't help you beyond that. I can build, but I don't understand electronics very well... :)

[RCFlyer55]

Martin,
I went to the site "NTE" and did as you said, but there were no Schottky diodes listed only Schottky Barrier Rectifiers. Are these the same thing?? None of the pictures(drawings) looked anything like what I have. Also I looked up Capacitors I know I need(or think) I need 0.047uf cermamic capacitors. They have 50V(8900 series) or 1000V (9000 series) which do I choose. The markings on the one I have is "473".

[mwraight]

try digikey.com too.

[MAVA]

RCFllyer55,

Sorry for the discription, the Name "Schottky Barrier Diodes" is the formal name. They are the same.
The one amp one is NTE585 and NTE586 is the three Amp.

I found them under General Purpose Diodes on the NTE website.

If you want one now!!, you can always desolder them from broken switching computer powersupply.
The Schottky's are located on the output side of the power supply(The side were the cables go to the Drives). They generaly will be on a heat sink.

Martin

[jeffs555]

The 473 on the your caps just means 47000pF ie .047uf and says nothing about the voltage rating. Generally, 50volt capacitors should be OK.