brucedp5 via EV wrote:
You are on the road again using another cursit controller. But for how long?
After my first curtis (cursit) controller died, and was replaced with
another by the converter... [it died again]
Bruce, there's a bit more to the story:
- This was about 15-20 years ago
- You were driving a heavy on-road vehicle
- You were using the smaller Curtis 1221, not the 1231
The Curtis 1221 was designed for industrial forklifts -- not on-road
EVs. EV usage is harder on the controller, because it is being asked to
deliver higher speeds and higher horsepower. It also has to survive in a
harsher environment; outdoors in all kinds of weather.
EV converters tend to "push" thing beyond their ratings, to save money
or get by with what was handy at the time. They often use parts right at
their absolute maximum ratings... no margin for error. If you use a
72-120v controller *at* 120v, it's going to fail sooner rather than later.
The 1221's were overloaded, and they failed. Curtis thus came out with
the 1232, and improved version built for on-road EV use.
The failure mode of your second controller sounds like a capacitor blew.
That throws conductive goo and aluminum foil all over the place inside
the case. This causes all sorts of additional short circuits and smoke
and fire.
My guess is that you were just off charge, so the pack voltage was
higher than 120v. Your EV converter may have installed a used or old or
lower-voltage Curtis 1221, whose capacitors weren't up to the task. Bang!
If having a lead foot (strong acceleration use) with the cursit will cause a
controller failure sooner, then isn't there a simple RC (resistor,
capacitor) circuit one could put at the cursit controller (pot-box) input
(slows the acceleration attack ramp to a slower rise, etc.)?
The Curtis has user-adjustable trimpots for current limit and
acceleration ramp-up. But as you might expect, most of the time someone
has turned them up to maximum. This is the go-fast / die-young setting.
--
Teaching children to program goes against the grain of modern education.
Just imagine the chaos if they learned to think logically, plan, create,
implement, test, and execute!
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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