do I properly size a speed controller to my motor?
You must know the stall current of your motor
before you can size any ESC for your application. Techniques
for determining this include manufacturer specifications and empirical
measurements. Note that "free running current" is NOT
the same as stall torque. The latter can be 4-5 times as high
as the former!
do I measure the stall current of my motor?
Buy a current shunt. Look in eBay. Shunts are nothing more than
calibrated resistance elements. You wire them inline with your
motor, attach your voltmeter to the shunt, lock the shaft of
your motor and power it up while reading your voltmeter. Most
shunts read a millivolt per amp which means that for every amp
flowing through the shunt, the voltmeter reads 1mV. If you see
85mV on the display, 85 amps are flowing through the shunt.
The ratio of mV/A is typically stamped onto the side of the
I didn't get
any of that. Can I just pay you to measure my motor?
My motor pulls
75 amps at stall. Will the Victor 883 work for me?
It will work beautifully.
My motor pulls
175 amps at stall. Will the Victor 883 work for me?
It is unlikely.
Wait a minute
- you list the Victor as one of the choices to run the Bosch
GPA750! What's the deal?
Alexander Rose used
this combo on the superheavyweight Toro at BattleBots without
any problems. He overcame the high stall current of the Bosch
by gearing it very low. This kept the Victor from melting. Obviously
there was a lot of engineering in place here way beyond the
simple "go, no-go" rules we all like to see. If you
can match him, the Victor will run your Bosch motor.
I didn't take
your advice above and it blew up. Can I fix it?
Unlikely. The driver chips are surface mount devices to reduce
space and the electronics are "potted" to keep conductive
crud out. You'll be fighting an uphill battle so best to spend
the effort working overtime at your job to buy a replacement.
Can you or
IFI repair it under warranty?
No, not if you exceeded the design current. If you are POSITIVE
you did not and it is still busted, contact IFI directly for
How high can
I push the 24v limit?
There is some safety margin to account for residual battery
charge (when fresh off the battery charger) but you should only
run the 24v Victor on two 12v gell cells or twenty 1.2v nicad
it that you must cut the red wire between the Victor and the
radio receiver. True?
Nope. It's a no-connect on the Victor PCB. The signal input
to the Victor is optoisolated so as to not transmit ground noise
back to the receiver. The only two wires that really count are
white (signal) and black (signal ground.)
I hooked everything
up properly and the the status LED just blinks. But when I plug
an R/C servo into the same receiver channel it works fine. Is
my Victor defective?
No you just need an inline signal buffer. Many radio receivers
cannot source enough current on the R/C signal line to drive
the Victor so an extra part is needed. Experience has shown
that most Futaba receivers require the buffer, Hitec do not.
The inline buffer is available from me, from IFI, and possibly
from your local hobby shop. Alternate names are "elevon
amplifier" and "long cable filter." We also sell
How do I get
a "tank drive" setup going on one transmitter stick
There are two ways. First you can just enable "elevon"
mixing in your transmitter if supported. Second, you can buy
one of my inline mixers (RCE540)
and install it between your Rx and the Victors. Note that if
you go with the inline mixer you do not need
any inline amplifiers as the mixer also takes care of this.
So that saves you some money!
Should I use
the jumper in "brake" or "coast" mode?
Brake gives sharper response at the expense of greater wear-and-tear
on your driveline mechanics. Coast is softer at the expense
of control response. Experiment and see which works best for
Can I replace
the supplied fan with a larger one and get higher current switching?
No, it has been aerodynamically tuned for the supplied geometry
as well as the PC board traces. Don't mess with it.
Can I add heat
sinks to the FETs get higher current switching?
No. Don't mess with them.
Can I run two
Victors in parallel to control a higher power motor?
No way. Manufacturing variations between the two will eventually
get them out of phase and they will fight each other. It's a
game that has one winner and one loser.
But wait! I've
heard of people running two Victors on a motor! What gives?
I too have heard of that configuration on motors that have a
pair of isolated brushes. Apparently the scheme
is to hook one Victor to each set of opposing brushes. Neither
Team Delta nor IFI support this application, so play the game
at your own risk!
Can I run two
motors with one Victor?
Yes you can run two motors in parallel off a single Victor as
long as both motors currents added together don't exceed the
max rating of the Victor. Note that since each Victor provides
ONE channel of control, and a tank-drive robot requires two
channels, you will need two Victors at a minumum if you want
to actually steer your robot.
Well if you're really pushing the current limit of the Victor,
mount the fan upward so that if the FETs desolder themselves
from the PCB at least they won't fall out!