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Canada
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Hello,

I have used servomotors from a developper kit (with EZ B 4) on a small robot and it works OK.

Now I want to use GM9 motoreductors (Solarbotics) instead.
So a got an EZ B H-bridge and noted connections used for Roli.

But I suppose that I have to add some protections between the EZB4 and the H bridge ? 
Or elsewhere,  so that no dammage happens . For EZB4 or H bridge.
What is necessary?

Thanks to help a beginner.

Cats92

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Canada
#1  
Have read part off this texts.

Rather asking myself if I have to add a freewheeling diode and/or  a fuse . Where  in my small robot ?

cats33
Synthiam
#2  
What hbridge did you get? With an hbridge you shouldn’t need any diodes or anything between the ezb. The purpose of the hbridge is to control the motors because the integrated circuit of micro controller can’t provide that amount of current on its own. 

The ezb should already be fuse protected if you’re using the power base from the developer kit - so you’re good to go:)
Canada
#3  
I get an hbridge from EZ ROBOT .

So 2 cables connected  between  D0 (red and black)  and the hbridge (vcc and gnd) provide enough current for 2  GM9  motors   ?
#4   — Edited
@cats33... No, you power the H-bridge separately via it's own VCC and ground... FYI you can use the same battery to do so...
Synthiam
#5  
Richard is right for large current hungry applications. You wouldn’t want to run large current through the circuitry of the ezb. The ezb can do hbridge of small motor, such that being used in the roli rover by EZ-Robot. 

Once you get into larger motors, such that wheel chair bases use or similar, then power the hbridge with its own batter. 

Just make sure the grounds are connected and shared
Canada
#6  
Thanks , it seems much clear .

cats33
Synthiam
#7  
No problem - the tough part is understanding when you  should take power from the EZ-B or take power directly from a battery. Ideally, it's nice to take power directly from the battery as often as possible because you will actually increase power efficiency. This is because a lot of current is actually lost in small wires due to resistance. Think of electricity like a garden hose for watering your lawn. If the hose is super thin, like a thin wire, not a lot of water is going to make it out the other end. 

I think of electricity as water like this...

Amps = the diameter of the garden hose
Volts = the water pressure