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INTRODUCTION
The RPM 13 and 15 relays mounted in '
an SI drawout case are general purpose
direct current operated auxiliary timing
relays having two cam operated closing
contacts.
Each contact has an independent
adjustable time setting with the exception
that the contacts must always close in the
same, sequenc.e with a minimum time of
several cycles between the closings of the
two contacts. Sl'!e the section on CHARAC-
TERISTICS for' further discussion of the
minimum time between contact closings.
Each contact has its own target and the
relay has one electrically separate seal-in
unit generally used with the TU-l contact.
In addition the RPM15 relay employes a
telephone type relay, TY, to provide a con-
tJm!PJ!s
~Qil n~tJng.
,S.ee Table No. A. for
different models.
APPLICATION
These RPM relays can be applied
wherever an accurate, direct current op-
erated, timing d.evice, .
.wJfu_
~_adjustable
timing ranges 0.1 to 1 second or 0.15 to 3
seconds is required: -A typical application
is illustrated in Fig. 4 where the RPM13
relay is used to provide a time delay before
the back-up fault relays
b~come
effective.
The fault relays together with the RPM re-
'lays are used here to provide back-up
protection for a unit type generator installa-
tion against P:rolongE!d multiphase faults on
the adjacent system. When the fault relays
operate, they start the RPM relay which
trips the main breaker after a predeter-
mined time thru its own TU -1 contact and
the fault relay contacts.
If
for some reason
the generator is still connected to the fault,
the fault relays will remain picked up and
when the second RPM contact (TU-2) closes
after an additional predetermined time it
will operate a lockout relay, Type HEA,
which shuts down the unit generator.
Fig. 5 shows the RPM15 relay sub-
stituted for the RPM13 relay in a similar
application.
, Tbe
RP~ re~ay
tripping- cpnt!ict.s @o:t,Il,c;I:
alwaysOe used
IIi
senes WIth the
lll-
itiating relay contacts in a trip circuit.
In ,this way any overtravel which may exist
in : the RPM relay is. negated by the opening
of the-initiating relay contacts.
TIMING RELAYS
TYPE'RPM
* TABLE A
TIMING
COILCmCUIT
CONTACT DWELL TIME
RANGE
TIME RATING
TU-l
TUc.2
~ODEL---
-
-
Seconds
Seconds
Cycles (60 Cycle Base)
12RPM13All & Up
0.15 - 3.0
60
9-15
9-15
12RPMI3B11 & Up
0.10 - 1.0
60
' Maintained
3,.5
12RPM13D11 & Up
0.15 - 3.0
60
Maintained
9-15.
12RPM15Al '& Up
0.15 - 3.0
.Continuous
9-15
Maintained
12RPM15Bl1 &
~
0.10 - 1.0
Continuous
Maintained
Maintained
12RPM15CL'&
p
'12RPMl5Dl: .&'Up
0.15 - 3.0
Continuous
Maintained
Maintained
,0.15 - 3,.0,
, COl;ltinuous
Maintained
' Maintained
RATINGS
These RPM relays are available with i
operating coils for' 24 to 250 volts D.C.,
As indicated in Table A the RPM13 relaysl
have coils rated for one minute and the
RPM15 relays have continuously rated coils.:
The target and seal-in units are current,
, operated devices with ratings of either 0.2
, or 1.0 amperes.
The timing contacts TU-1 and TU-2
are for circuit closing only.
They will,
carry a maximum of 30 amperes for the
time it takes to trip a breaker and have no
interrupting rating.
Since these contacts
have no, interrupting rating, any control
circuit involving these contacts must be
cleared by a circuit breaker auxiliary switch
or other suitable
means~
The contact interrupting rating of the
telephone type relays are shown in Table B.
'The contact rating of the seal-in unit
is shown in Table C.
CONTACT INTERRUPTING ABILITY
TABLE :i3
..
'-
TARGET AND SEAL-IN UNIT
TABLE C
,1~()'Amp
'0.2 Amp'
~'Tap
Tap
DC Resistance
O,2;L'ohms
;jl ..
:ohms
Minimum Operating
l~O,amps
0 •. 2 amps
Carry Continuously
;2 ..
.if:amps
0.35 amps
Carry 30 amps for
'2
sees.
---------
Carry 10 amps for
15 secs.
0.2 flecs.
60-cycle Impedance :2.0: ohms 52 ohms
CHARACTERISTICS
OPERA TING PRINCIPLE
The
RPM relay
operates
on the
prinCiple of using the energy from a charged
spr.ing.
The spring is charged by a solenoid
called a rotonoid because of its circular
shaped plunger.
The energy of the spring
is diSSipated through a gear train at a rate
controlled by a damping magnet. The timing
contacts are operated by cams attached to,
this gear train.
,
The TX coii of the RPM relay has a
very low drop-out voltage. This low drop-
out makes it possible for an indicating
lamp in series with the, TX coil to keep
that
el~mentpicked
up after it has operated.
For thIS reason it is important that caution
be
~xercised
in the application of the relays
to msure that there are no sneak circuits
which can permit the TX coil to be sealed
in through a lamp or some other device.
Volts
Interruption Current' (Amps)
MINIMUM OPERATING VOLTAGE
Inductive*
Non-Inductive
48-DC
1.0
3.0
125-DC
0.5
1.5
250-DC '
0.25
0.75
115-60 cy.
0.75
2.0
230-60.cv.
0.5
1.0
* Inductance of Average Trip Coil
The operation of ,the rotonoid desig.;
nated as "Tun is controlled by the contacts
of the telephone type relay designated as
"TX".
.
Both this telephone type reiay "TX", and
the telephone type relay "TY" which is used
in the RPM15 relays will operate at 80% of
rated voltage or above.
These instructions do not purport to cover all details or variations in equipment nor to provide for every poaib/e
contingency to be met in connection with installation, operation or maintenance. Should further information be desired
or should particular problems arise which are not covered sufficiently for the purchaser's purpases, the matter should
be referred to the General Electric Company.
3
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