Eaton Digitrip 520MCV, Instructions Manual

Effective 8/2006

Page 15

I.L. 66A7534H04

Connector

(Storage)

“LTM Active

”

Connector

(Bridging)

“LTM Inactive

”

Test

Kit

Test

Kit

(Also Recommended

Position for 

Field Testing)

Digitrip Test Kit Port

Notch

Available Settings

1.5, 2, 3, 4, 6,  8,  10,  M1

In Multiples of 

Long Delay Setting ( r)

I

Short Delay
Setting

M1 Value is Specified on Rating Plug

2 x  r

I

Figure 4.5  Short Delay Time Settings

Five FLAT (.1, .3, .4, .st1,st2 seconds) and three I

2

t (.1*,

.3*, .5* seconds) response time delay settings are avail-
able. The I

2

t response settings are identified by an asterisk

(*). The time settings labeled st1 and st2 are based on the
rating plug. For 100A st1 and st2 =0.5s. For 200A through
400A, st1 = 0.5s and st2 = 1s. For rating plugs  600A and
greater, st1 =1s and st2 = 2s.The I

2

t response is appli-

cable to currents less than 8 times the ampere value of 

I

r

rating. For currents greater than 8 x (

I

r)

the

I

2

t response

reverts to the FLAT response.

NOTE:

  Also see Section 3.3 - Zone Interlocking.

4.6  Instantaneous Current Setting

There are eight available 

Instantaneous

 current settings,

as illustrated in Figure 4.6. Six settings are in the range
from 2 to 10 x (

I

n) the rating plug value, and the other two

settings are M1 x (

I

n) and Off. The value that M1 has

depends upon the plug rating of the circuit breaker and is
specified both on the rating plug label and on the
applicable time-current curves referenced in Section 9.

Figure 4.3  Long Time Memory (LTM) Jumper

The action of the LTM must be considered when performing
multiple 

Long Delay Time

 tests 

(See Section 5.4).

4.4  Short Delay Current Setting

There are eight available “Short Delay Current Settings,” as
illustrated in Figure 4.4. Seven settings are in the range
from 1.5 to 10 times (

I

r). However there exists an addi-

tional  maximum setting M1 that is based on 

(In)

.It is set

for 14x (

In)

 for all rating plugs up to 1250A and 12X for

2000A, 2500A.

REMINDER:

 (Ir) is the “Long Delay Current Setting.”

Figure 4.4  Short Delay Current Settings

4.5  Short Delay Time Setting

As illustrated in Figure 4.5, there are two different “Short
Delay” response curve shapes: fixed time (FLAT) and I

2

t.

The shape selected depends on the type of selective
coordination chosen. The I

2

t response curve will provide a

longer time delay for current below 8 x 

I

r than will the FLAT

response curve.

. ,. ,. ,  ,

1 3 4 st1 st2

PLUG

st1

st2

100A

0.5

200-400A

0.5

0.5

1.0

1.0

2.0

600-2500A