Emax UL
28/132
L2275
Doc. N°
Mod.
RH0109002
Apparatus
Scale
Page N°
12.
SACE PR111/P-A trip unit – Identification
The PR111 units available according to the ANSI/UL Standards are:
•
PR111/P-A (LI)
•
PR111/P-A (LSI)
•
PR111/P-A (LSIG)
12.1 Standard
PR111/P-A has been designed to work in accordance with the international standard:
Low voltage AC and DC power circuit breakers used in enclosures ANSI/UL 1066.
12.2 Specifications
12.2.1 General
The PR111 unit is a high performing self-supplied protection unit with Protection, Watchdog and Test functions.
The protections available are:
Protections available
Symbol
Protection against…
L
overload with inverse long time-delay
S
short circuit with adjustable delay
I
instantaneous short circuit
G
ground fault with adjustable delay
Iinst
ultrarapid instantaneous short circuit (for high currents)
The PR111 can be installed on three-pole, three-pole with external neutral or four-pole power circuit breakers.
It should be noted that the reference current, for the PR111, is the In (continuous current rating of the CTs mounted in the power circuit breaker)
and not the Iu (uninterrupted continuous current rating of the power circuit breaker itself). Example: the E1B-A 800 power circuit breaker with 250
A CT, has an Iu of 800A and an In of 250 A.
The unit carries out opening of the power circuit breaker, in which it is integrated, by means of the SA which acts directly on the mechanical lever
device of the apparatus.
The CTs supply both the energy for self-supply and the signal to calculate the current circulating in the power circuit breaker busbars to the trip
unit. Operation with self-supply is guaranteed for any protection function and setting which can be defined by the user.
The unit is made using digital microprocessor technology and interfaces with the user by means of dipswitches. The protection parameters and
in general the mode of operation of the unit can be completely set by the user.
12.2.2 Electrical characteristics
Nominal service frequency
50/60 Hz ±10%
Pass band
600 Hz max
Peak factor
2.1 max @ 2.8 In
MTBF
15 years @ 45°C
12.2.3
Self-supply
All the Protection functions (see par. 12.2.1) are operative without any external auxiliary power supply. In fact, self-supply is guaranteed from the
CTs installed in the power circuit breaker.
Minimum busbar current for turning the trip unit on:
– 0.30xIn with single-phase current
– 0.20xIn with two-phase current
– 0.15xIn with three-phase current
12.3
Environmental characteristics
Operating temperature
-25°C ... +70°C
Storage temperature
-40°C ... +90°C
Relative Humidity
0% ... 98%
Degree of protection (with PR111 installed in the power circuit breaker) IP 30
12.4 Protection functions
The PR111 protection unit carries out 5 independent protection functions. In particular:
1. Protection against overload with inverse long time-delay “L”;
2. Protection against short circuit with adjustable delay “S”;
3. Protection against instantaneous short circuit “I”;
4. Protection against ground fault with adjustable delay “G”;
5. Protection a fixed threshold against instantaneous short circuit “Iinst” ;
The unit is fitted with “backup protection” function. Should the first strike on the opening solenoid not immediately open the power circuit breaker
(SA partially faulty), TRIP commands are sent repeatedly until the power circuit breaker opens or until disappearance of the current.
The PR111 unit allows the neutral pole current signal to be processed with different relationships with regard to the value of the phases (see 12.9.1).
Two luminous indicators (LEDs) are provided on the front of the unit, which are activated during an alarm for protection “L” or “S”. They are de-
activated on ending of the alarm or when a protection has tripped.
For the protections with fixed time with adjustable delay, the relationship implemented is the following: t = k.
For the protections with inverse time, the relationship between trip time and overcurrent is given by the formula: t = k / I2.
