Jake Brakes & dynos

[Doug Rorem]

>>What is typically used for the source of the electric current?  me

I assume it's the vehicle's 12V (or 24V?) electrical system. The Jacobs
Driveline brake takes quite a bit of current (249 Amps worst case!).
This would mean a fairly hefty power source would be required for use
in a dyno. They (Jacobs) also don't really say what the duty cycle of
the device is.. It probably overheats if you try to use it continuously.
As someone noted previously, it seems easier to create rotating energy
than it is to get rid of it!

 [table from] http://www.jakebrake.com/products/perftables/tDriveBrake.html

Jacobs   Braking     Max. Brake Weight   Amperage  Max.       Vehicle Weight
Models   HP at RPM*     Torque     (lbs.)   Drawn     Stop & Go  weight Long
                     (ft lbs)**          (Amps)               Descent (lbs)

12JC10   134 @ 2500  289        154      115       13,800     8,000
12JC12   152 @ 2500  362        225      123       15,400     8,800
12JC16   198 @ 2500  470        227      149       17,600     11,000
12JC20   265 @ 2500  579        267      166       19,800     13,200
12JC25   332 @ 2500  723        322      145       28,600     15,400


12JC30   403 @ 2500  868        379      249       39,000     26,000
12JC40   483 @ 2500  1,157      534      177       41,800     33,000
12JC50   559 @ 2500  1,447      736      187       48,400     37,400
12JC65   728 @ 2500  1,881      864      184       96,800     73,700
12JC75   766 @ 2500  2,170      948      197      110,000     83,600

12JC80   817 @ 2500  2,315      977      213      110,000     88,000
12JC10LC 134 @ 2500  289        267      41.1      13,800      8,000
12JC12LC 152 @ 2500  362        322      36.3      15,400      8,800
12JC16LC 198 @ 2500  470        379      62.25     17,600     11,000

* Estimated
** Torque values are a more precise measurement of braking performance.

>>
>>At 03:23 PM 9/18/96 -0500, you wrote:
>>>>>What is an EMF retarder?
>>>>>
>>>>>-- J.
>>>>>
>>>EMF = ElectroMagnetic Force
>>>
>>>from http://www.jakebrake.com/products/theory/dlbtheory.html
>>>
>>>The Jacobs Driveline Brake is an electro-magnetic supplemental braking
>>>system that is mounted between the vehicle's transmission and rear axle.
>>>When an electric current is fed to the brake, it passes through coils and
>>>creates a magnetic field.  This magnetic field creates drag. This drag
>>>opposes the normal rotation of the driveshaft, thereby slowing the
>>>vehicle down.
>>>

--
Doug Rorem
University of Illinois at Chicago         (312)-996-5439  [voice]
EECS Department  RM 1120                  (312)-413-1065  [fax]
851 S. Morgan Street                      (708)-996-2226  [pager]
Chicago, IL 60607-7053                    rorem at uic.edu