[PRCo] Re: Interurban PCCs ???

[Boris Cefer]

Slippage, skid.
The slip relays provided protection of main motors against excessive speed
due wheel slippage or they prevented creation of flat spots on wheels in
braking.
In acceleration the relays inserted some resistance in the power circuit
reducing the motor torque. In braking they inserted field shunts with the
same effect on the main motors - reduction of braking torque.

By the way, it looks that Westinghouse 14s and 15s had SG (speed governor ?)
relays. But I can't find them in schematic diagrams.

B

----- Original Message -----
From: "James B. Holland" <PRCoPCC at P-R-Co.com>
To: "- 1714 PRCo__WP__JTC -" <pittsburgh-railways at dementia.org>
Sent: Sunday, March 27, 2005 10:02 AM
Subject: [PRCo] Re: Interurban PCCs ???


> What is a Slip Relay, Please?
>
> Jim
>
>
>
> Boris Cefer wrote:
>
> > That's a good idea! Ed, can you hear us? Put on your overalls :-)
> >
> > At this point we don't know what field shunting equipment the GE  16s
> > and 17s had (unfortunately there is no GE car to look at :-( ), but
> > there is at least evidence that GE 16 had overspeed protection. Now I
> > see in the GE parts catalog that also GE 17s had overspeed relays!
> > This "may" suggest that also GE cars were capable of higher speed.
> >
> > Several PCC series had also slip relays (both W and GE 14s, 15s and
> > 16s), but it appears that they were removed or at least deactivated.
> >
> > B
> >
> > ----- Original Message -----
> > From: "James B. Holland" <PRCoPCC at P-R-Co.com>
> > To: <pittsburgh-railways at dementia.org>
> > Sent: Sunday, March 27, 2005 9:05 AM
> > Subject: [PRCo] Re: Interurban PCCs ???
> >
> >
> >> Another clarification. As we are talking about only the 1700--1774 WH
> >> cars, the same holds for the 1600 and 1601--1674 cars -- we do not
> >> know about GE in either series -- correct?
> >>
> >> Yes, PRCo trackage was rough relative to other properties, but it was
> >> in the early 1960s when I experienced the governor cut-out of power
> >> on both the 17s and 16s -- you could still get those cars rolling
> >> very nicely!
> >>
> >> Maybe Ed could check those jumpers on 1711 as Hands-On Training for
> >> his Electrical Engineering Degree!!!
> >>
> >> Jim
> >>
> >>
> >>
> >> Boris Cefer wrote:
> >>
> >>> But the earlier books appear more detailed.
> >>> There are possibly some data in GE wiring diagrams, but I haven't
> >>> seen any except for the early air cars (1000-1200 series), but they
> >>> don't make me happy because the early GE design was terribly
> >>> complicated. GE  parts catalogs do not contain any useful data,
> >>> these are endless lists of parts with some pictures only.
> >>>
> >>> And an another question is still the Westinghouse 1700s. Their
> >>> equipment allowed to change the balancing speed by means of higher
> >>> field shunting. Only four small jumpers joined to the field shunting
> >>> resistors increased the balancing speed several mph, but we don't
> >>> have any evidence whether PRCo or later PAAC did not dismantle them
> >>> to avoid eventual accidents due extremely high speed over irregular
> >>> track. Memory is sometimes very delusive and some few can tell us
> >>> what the top speed was 50 years back. Our friends at PTM would have
> >>> to check whether the jumpers on 1711 are in place...
> >>>
> >>> B
> >>>
> >>> ----- Original Message -----
> >>> From: "James B. Holland" <PRCoPCC at P-R-Co.com>
> >>> To: <pittsburgh-railways at dementia.org>
> >>> Sent: Saturday, March 26, 2005 10:17 PM
> >>> Subject: [PRCo] Re: Interurban PCCs ???
> >>>
> >>>> Time to speculate why GE was so Resistant to include specific
> >>>> information!! :-)
> >>>>
> >>>> Various PCCs had been *tested* for interurban service according to
> >>>> that 1952 ERA type dissertation on the PRCo Interurbans as well as
> >>>> the Ira Swett article on Charleroi -- but they weren't specific
> >>>> about the tests and whether or not the PCCs were run beyond Library
> >>>> -- we know that they were used as trippers this far and even the
> >>>> PTM calendar shows an 1100 used for Fair Grounds tripper about 1949
> >>>> or 1950.
> >>>
> >>>> With 1613 and 1614 converted for interurban Test service within
> >>>> 6-months of delivery (at least for 1613) PRCo was *probably*
> >>>> considering PCCs for interurban service even as the 1601s were
> >>>> ordered. Guess we shall never know For Sure without something
> >>>> turning up in the archives.
> >>>
>
>