Siemens 3RB20 참조 매뉴얼 - 페이지 10

{카테고리_이름} Siemens 3RB20에 대한 참조 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. Siemens 3RB20 46 페이지. Protection equipment, overload relays
Siemens 3RB20에 대해서도 마찬가지입니다: 사용 설명서 (6 페이지), 운영 지침 (4 페이지), 매뉴얼 (18 페이지)

페이지 인쇄

Overload Relays

3RU1 Thermal Overload Relays

3RU11 for standard applications

■

Function

Basic functions

The 3RU11 thermal overload relays are designed for:

• Inverse-time delayed protection of loads from overloading

• Inverse-time delayed protection of loads from phase failure

Control circuit

The 3RU11 thermal overload relays do not require an additional

supply voltage for operation.

Short-circuit protection

Fuses or motor starter protectors must be used for short-circuit

protection.

For assignments of the corresponding short-circuit protection de-

vices to the 3RU11 thermal overload relays with/without contactor

see "Technical specifications" and Catalog LV 1, "Selection and or-

dering

data".

Trip classes

The 3RU11 thermal overload relays are available for normal star-

ting conditions with trip class CLASS 10. For heavy starting con-

ditions see 3RB2 solid-state overload relays.

For details of the trip classes see "Characteristic

Phase failure protection

The 3RU11 thermal overload relays are fitted with phase failure

sensitivity

(see "Characteristic Curves")

perature rises of the load in the case of a phase failure during sin-

gle-phase operation.

Setting

The 3RU11 thermal overload relays are set to the rated motor cur-

rent by means of a rotary knob. The scale of the rotary knob is

shown in ampere.

Manual and automatic reset

Automatic and manual reset is selected by pressing and turning

the blue button (RESET button). If the button is set to manual reset,

the overload relay can be reset directly by pressing the

RESET button. Resetting is possible in combination with mechani-

cal and electrical reset options from the range of accessories

Catalog LV 1,

"Accessories"). If the blue button is set to automatic

RESET, the relay is reset automatically.

The time between tripping and resetting is determined by the re-

covery time.

Siemens · 2011

Recovery time

After tripping due to overload, the 3RU11 thermal overload relays

require some time until the bimetal strips have cooled down. The

device can only be reset after the bimetal strips have cooled

down. This time (recovery time) depends on the tripping charac-

teristics and strength of the tripping current.

The recovery time allows the load to cool down after tripping due

to overload.

TEST function

The TEST slide can be used to check whether the operational

3RU11 thermal overload relay is working properly. Actuating the

slide simulates tripping of the relay. During this simulation the NC

contact (95-96) is opened and the NO contact (97-98) is closed.

This tests whether the auxiliary circuit has been correctly connec-

ted to the overload relay. If the 3RU11 thermal overload relay has

been set to automatic RESET, the overload relay is automatically

reset when the TEST slide is released. The relay must be reset with

the RESET button if it has been set to manual RESET.

STOP function

If the STOP button is pressed, the NC contact is opened. This swit-

ches off the contactor downstream and thus the load. The load is

Curves".

switched on again when the STOP button is released.

Display of the operating state

The respective operating state of the 3RU11 thermal overload re-

in order to minimize tem-

lay is displayed by means of the position of the marking on the

TEST function/switch position indicator slide. After tripping due to

overload or phase failure, the marking on the slide is to left on the

"O" mark, otherwise it is on the "I" mark.

Auxiliary contacts

The 3RU11 thermal overload relays are fitted with an NO contact

for the tripped signal, and an NC contact for disconnecting the

contactor.

(see