Subject:
|
(no subject)
|
Newsgroups:
|
lugnet.robotics.handyboard
|
Date:
|
Fri, 5 Jul 1996 20:57:30 GMT
|
Original-From:
|
System User <lylehaze@n-AVOIDSPAMjcenter.com>
|
Reply-To:
|
Lyle Hazelwood <lylehaze@n=antispam=-jcenter.com>
|
Viewed:
|
1574 times
|
| |
|
|
Oh well, I THOUGHT I was done with my H-Bridge.. It seems to be running a
bit hot. I had originally tested the motors with a bench supply, and the
current never exceeded five amps, so I thought the TIP 120/125 circuit was
"just right". It now seems that the bench-supply I was using is limited to
five amps of output (Oops). Testing on the robot shows about eight amps per
motor at startup, eventually coming down to five after the wheels (big
wheels) come up to speed. This is with the 'bot "up on blocks", not
actually pulling it's own weight. I need a bigger H-Bridge! So far, I am
checking two options. I have located Darlington transistors that can handle
10 continuous/15 surge. This seems a bit tight, still, since my heatsinks
are not as large as I would like. I also have some IRF640/IRF9640 MOSFET
pairs on hand.. This sounds ideal, but I am not familiar with the changes
that would be needed in the circuit. I saw a brief mention of MOSFET's in a
previous posting by Chuck. Would the change from TIP120/125's to these
MOSFET transistors be a difficult one? If I can't figure this out, I may
need to go to smaller motors. Thanks for any assistance!
P.S., yes, this 'bot is big and heavy.. using a motorcycle battery for motor
power and a pair of gearmotors hacked from cordless drills. Wheels are 14"
bicycle tires, on plastic "mag" style rims, gear driven, with quad encoders.
(at least wheelspin won't be a problem!)
Lyle Hazelwood (lylehaze@n-jcenter.com)
|
|
1 Message in This Thread:
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
