[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: (ET) Hybrid Electrak?
On 1/15/2011 10:35 AM, Banks, Michael J. wrote:
I was under the impression, that using the tractor while charging was a
bad thing.
That depends on the charger. There are a couple of circumstances where
using a charger on a running EV could cause damage.
- The noise from the charger could damage control electronics or simply
cause it to be confused. The battery does act as a nice filter for
lower frequency disturbances though.
- The charger cannot react quickly to load changes(0). EVs will
produce rapid load changes. The worst case is probably going from full
torque to zero torque(1). All of a sudden the voltage will rise as the
current is diverted to the battery. This could damage the control, the
charger or the battery if not limited. A near fully charged battery
will be more of a problem in this case.
- It would also play havoc with any charger's end of charge
determination.
However given a good clean DC source with a good fixed maximum voltage
with a fast response there is no reason to expect a problem. A PM motor
rotating at a fixed (or strictly limited maximum) speed is almost ideal
for this.
Robert
0 - This is part of the reason that you'll often see chargers say the
charger must be off before disconnecting the battery, they cannot react
to the sudden load change quickly enough.
1 - Even worse is on an EV with regen when you go from full torque in
one direction to full torque in the other. Imagine the following
scenario. Vehicle takes 200A from the bus in full acceleration, battery
provides 100, charger provides 100. The vehicle then switches to full
regen returning 200A to the bus. The battery has now one from sourcing
100A to sinking 300A (100A charger, 200A regen). Now regen and accel
currents will not often be this symmetric but it should be obvious that
dramatic changes in current at the battery are possible complicating the
charger's needed response.
--
http://www.aeolusdevelopment.com/
From the Divided by a Common Language File (Edited to protect the guilty)
ME - "I'd like to get Price and delivery for connector Part # XXXXX"
Dist./Rep - "$X.XX Lead time 37 days"
ME - "Anything we can do about lead time? 37 days seems a bit high."
Dist./Rep - "that is the lead time given because our stock is live....
we currently have stock."