2495's Shootin

[Dale(294engr]]

SAFETY FIRST!!! Please!! Never ever power motor directly from battery without a fuse or circuit breaker!

Breaker/Fuse is essential 1st line of safety. Especially in quickie tests

2nd line:Anderson disconnect but actively requires someone to act fast and not be entangled in the emergency such as clothes, finger binding in a chain /gear, etc

Simple enough to wire a 40A circuit breaker in series with a motor lead!!

(<<40A preferred for greatest safety margin,
selected per application
start w/20A,
ease up to 30A or 40A as needed)

Preferred is lever action circuit breaker to act as switch in lieu of plug / unplug clunky Anderson connectors as shown in video.

FYI:
Circuit Breakers are designed to HOLD at marked amperage. They break / open starting at ~125% of rating depending on amplitude & duration of over current

so 40A starts opening at 1.25*40 = 50A (cycling starts or fixed type trips)

Do view mfr CB data sheet curves detailing this dynamic!

Safety FIRST!! not an option!

FACT: when you disconnect CIM running at full speed the voltage at the separating ends rises abruptly reaching thousands of volts??

causing a visible arc!! due to the motor inductance..

former energized field collapses/cuts through copper windings, inducing a high voltage limited only by load (Vpk=dI/dT) theoretically goes to infinity!!
but practically limited by arc over at opened conductors or insulation breakdown to less than infinity!!

Check it out: use oscilloscope to view voltage peak with suitable scope probe 100 Megohm suggested 1000 Mohm better so as not damage sensitive scope input placed across motor side leads and to minimize load to see actual Vpk minimal load burden.

(lower measurement probe resistance loading decreases observed Vpk,
broadens attenuates observed impulse duration but brighter viewed on scope screen,
relative to objective to measure unloaded open circuit peak voltage)

If a human is in close proximity or in contact with i.e. holding both motor leads when motor power is interrupted,
the inductive kickback energy will cause a very memorable shock experience!!

(Human becomes motor load resistance and need only be in close proximity to leads
say .1" as inductive kickback voltage rises high enough to jump/arc to conductive skin!)

Jaguars & Victors have special internal protection devices to handle steer / recover this energy,
else output FETs suffer catastrophic punch thru, smoking them

in spite of best design punch thru still occurs albeit less frequent but dramatically as
smoke clouds rise from robot motor controllers in competition every year!