Siemens PTS-4 - Testing Procedures and Device Types

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Testing First Generation Trip Devices

Bench Testing

The alligator clips described previously are also used to make

connections to the first generation trip devices for bench

testing, so connections and procedures are the same as

when testing with the device on the circuit breaker.

1. Types

A — Dual Static (long time an instantaneous

elements).

C —Dual Static Selectable Time Band and

high range instantaneous.

D —Selective Static (long time and short time

elements)

AG —Dual Static with ground fault element for 3

wire circuits.

DG —Selective Static with ground fault element

for 3 wire circuits.

4WAG —Dual Static with ground fault element for 4

wire and 3 wire circuits.

4WDG —Selective Static with ground fault element

for 4 wire and 3 wire circuits.

2. The pick-up settings of the instantaneous and short time

delay elements are calibrated at 3, 5, 8 and 12 multiples

of the long time delay pick-up setting.

3. The maximum interrupting time is the maximum length

of time that fault current flows, including arcing time.

4. Instantaneous maximum interrupting time may be greater

when breakers are closed in on a fault depending on

actual fault conditions. The maximum potential increase

for a 3 phase fault is 0.01 seconds and for a single phase

ground fault is 0 02 seconds.

5 The lower limit of ground fault recognition is 25 amperes

for an LA-600 breaker. For an LA-1600 breaker the

lower limit is 40 amperes. Application of Models 4WAG

and 4WDG is not recommended for LA-600 breakers

having a minimum continuous current setting of less than

75 amperes or an LA-1600 breaker with a minimum

continuous current setting of less than 200 amperes.

Dual Device

MODEL A—general purpose device normally used for phase

overcurrent protection. The pick-up range is selected from

the trip rating table and is continuously adjustable from “A”

through “E” in the field. The instantaneous element is continu-

ously field adjustable from 3 to 12 multiples of the long time

delay pickup settings selected. The time delay band is

selected and set at the factory—it is not field adjustable.

Available time delays are minimum, intermediate and maxi-

mum

MODEL AG (optional)—provides phase overcurrent protec-

tion plus sensitive ground fault overcurrent protection for

systems with phase-to-phase loading. Ground current pick-

up settings are independent of the phase pick-up settings,

and continuously adjustable in the field from 20% through

80% of the minimum phase pick-up setting shown in column

“A “

MODEL 4WAG (optional)—provides phase overcurrent pro-

tection plus sensitive ground fault overcurrent protection for

3 wire and 4 wire circuits for systems with phase-to-neutral

loading. Ground current pick-up settings are independent of

the phase pick-up settings, and continuously adjustable in

the field from 20% through 80% of the minimum phase pick-

up setting in column “A.”

MODEL C (optional)—Dual Static Selectable Time Band and

high range instantaneous.

MODEL D (optional)—an overcurrent trip device which pro-

vides time delay tripping only. It allows field adjustment of

long time delay and pick-up and short time delay and pick-

up. The continuous adjustment feature allows a setting

selection anywhere within calibrated points. The user can

adjust the current at which the device transfers from long time

to short time delay between these limits. Any one of the three

short time delay curves can be chosen to be used with any

of the three long time delay curves.

MODEL DG (optional)—provides phase overcurrent protec-

tion plug sensitive ground fault overcurrent protection for

systems with phase-to-phase loading. Ground current pick-

up settings are independent of the phase pick-up settings,

and continuously adjustable in the field from 20% through

80% of the minimum phase pick-up setting shown in column

“A.”

MODEL 4WDG (optional)—provides phase overcurrent pro-