[PRCo] Re: The final brake

[Fred Schneider]

Corrected copy

On Sep 1, 2007, at 6:22 PM, Fred Schneider wrote:

> Brakes are unaffected by loss of 600 volts except that you cannot
> release them again.
>
> 1.   You can apply brakes.   The battery will spin the pilot motor
> backwards which will maintain steady dynamic brakes as the car slows
> down.
>
> 2.   When the dyanics FADE, the lock out relay (32 volts) will allow
> the drum brakes to come on.
>
> 3.  If you need them in emergency, the track brakes can be energized
> from the batteries as always.
>
> 4.  But you need 600 volts to release on the windings of the drum
> brake release solenoid.   With the pole off the wire or a substation
> down, you cannot release the brakes.   However, you can manually wind
> off the brakes and push the car off the street with the truck.
>
> 5.  If the battery is stone cold dead, pray for something soft in
> front of you.   Not only will none of the relays work but the pilot
> will also not work to notch the accelerator backwards to cut out
> resistance.  I suspect pushing the reverse bar all the way forward
> will buck the motors with no resistance and maybe the car will get
> down to 1 mph before you burn out or flash over a motor.   I've been
> told it is the trick of last resort.
>
> Sufficient answer?
>
>
>
> On Sep 1, 2007, at 5:55 PM, ROBERT R ROCKWELL wrote:
>
>> So, in the case of a complete  power failure on an ALL electric
>> car,  which is the last resort ? A motor drum brake spring loaded
>> (reduction type brake), or a magnetic track brake fed from 32 v
>> batteries ?
>> Robert Rockwell
>> w3syt1 at msn.com<mailto:w3syt1 at msn.com>
>>   ----- Original Message -----
>>   From: Boris Cefer<mailto:westinghouse at iol.cz>
>>   To: pittsburgh-railways at dementia.org<mailto:pittsburgh-
>> railways at dementia.org>
>>>>> followed by a mechanic brake,
>>   wheel tread brakes operated by air on earlier PCCs or motor drum
>> brakes controlled electrically on most postwar cars.
>>
>
>