|
|
| Re: SEPTA ACS-86 question (1358759) | |||
 |
|||
| Home > SubChat | |||
|
[ Read Responses | Post a New Response | Return to the Index ] |
|
||
|
Re: SEPTA ACS-86 question |
|
|
Posted by Bill West on Mon Jul 6 14:54:59 2015, in response to Re: SEPTA ACS-86 question, posted by Jersey Mike on Mon Jul 6 09:49:34 2015. at 500-600hp a car, a 6-car train of MU's would draw less power at peak load than an 8600hp electricOkay but the engineer on an 8600hp loco hauling 6 coaches with the same schedule as the MUs shouldn't notch out to more than 3600hp or he will arrive early. (Increase slightly for loco weight, reduce slightly for lighter car weight). Applying the full 8600hp is a change in acceleration rate, so a change in schedule and would make the basis for comparing electric loads unequal. Regarding the substation rebuild, SEPTA could: -install bigger transformers with circuit breakers having higher load current ratings and run heavier conductors throughout or -install transformers with lower impedance and substation/car circuit breakers having higher short circuit interrupting ratings (to handle the resulting higher fault currents. Transformer impedances run 5 to 10%, one divided by the impedance, times the rated current defines the maximum short circuit current. A 1000 amp 10% transformer can deliver 10,000 amps into a short). The trade off for accepting the higher fault currents is that the lower impedance gives a lower voltage drop. Both are costly but if they just stick to renewal and don't add in one of these then there will be no change in the limiting voltage drops and thus the system capacity will stay the same. We're back to: if the ACS-64's are given the same assignments as the AEM-7s then there will be no change in electric load; if the trains/schedules change the electric load will change but, for newer schedules within the AEM-7's ability, which locomotive won't be the difference. Bill |
|
|
|