New elec Kb lv User manual

Overload (for both cyclic and sustained overload conditions)

Single phasing / unbalance

Undercurrent / load loss

Overload protection is provided against cyclic and sustained overloads. Pre-loading with thermal memory,

utilising accurate hot and cold thermal curve characteristics to IEC 255-8 provides this protection. The thermal

IDMT curve is Class 15 cold and Class 5 hot. This curve will provide adequate protection in the event of a motor

stall, both during starting and running conditions.

Should the motor load exceed the thermal capacity allowed by the thermal IDMT curve (Class 15 cold and Class

5 hot curve) the motor overload LED indicator will be illuminated, the relay healthy indicator switched off and

the main trip relay de-energised to stop the motor.

The same motor overload LED can be used to read the actual load current being drawn by the motor during

normal running conditions. This is achieved by pressing and holding the control panel mounted reset

pushbutton, while trimming back the maximum load current dial, until the motor overload LED switches on.

The calibration on the max load current dial at which this occurs is the actual load current being drawn by the

motor.

In the event of a motor overload trip the entire thermal capacity of the motor has been utilised. If auto reset has

been selected the motor overload LED will flash at a one-second rate until the thermal capacity has integrated

to 33%. At this point the overload LED will switch off and the relay healthy LED will switch on to indicate that

the motor can be returned to service. The relay will reset to a Class 5 hot curve.

298 Soutter Street, Pretoria West

Postnet Suite #73, Private Bag X06, Quagga, 0058

Tel: (012) 327-1729 Fax: (012) 327-1733

E-mail: [email protected] Http://www.newelec.co.za

KB LV Motor Protection Relay

INSTALLATION AND SETTING UP PROCEDURE

Example 1:

Protection for 3 kW 380 Volt three-phase motor

Motor full load 6,5 Amp

Suggestion:

KB10 / 380V

Example 2:

Protection for 132 kW 525 Volt four-pole, three-phase motor

Motor Full Load 175 Amp

KB200/525/200:5

Ordering examples for the various models

Interposing secondary

Model or relay type Current setting range current transformer

ratio where required

KB 1 0,1 to 1 Amp Not required

KB 5 0,5 to 5 Amp Not required

KB 10 1 to 10 Amp Not required

KB 25 2,5 to 25 Amp Not required

KB 50 5 to 50 Amp 50:5 Class 1 2,5 VA

KB 100 10 to 100 Amp 100:5 Class 1 2,5 VA

KB 200 25 to 200 Amp 200:5 Class 1 2,5 VA

1. Protection Features

2. Description of Operation

10. Ordering Information

If manual reset is selected, the motor overload LED will remain on until the control panel mounted reset button

is pressed. If the reset pushbutton is pressed and the thermal capacity has not integrated to 33% the auto-

reset sequence is initiated. If the thermal capacity has integrated to >33% then the overload LED will switch

off, the relay healthy LED will switch on and the main trip relay will be re-energised and the motor returned

to service.

Phase unbalance protection is provided independent of motor load. In the event of the three line currents

becoming unbalanced by more than 30% a 5 second trip delay is initiated. After tripping, the phase unbalance

LED will be illuminated, the relay healthy indicator switched off, and the main trip relay de-energised to stop

the motor.

Should the motor load current, during normal operation, drop below the minimum load % MLC dial setting,

while still being >10% of the maximum load current dial value for the full 10 second period, the minimum

load LED will be illuminated, the relay healthy indicator switched off, and the main trip relay de-energised to

stop the motor.

If, during the 10 second trip time period, the motor load current increases above minimum load % MLC dial

setting, and then once more drops below the minimum load % MLC dial setting value, a new 10 second trip

delay period is initiated. The minimum load value can be adjusted during normal running conditions by

pressing and holding the control panel-mounted reset pushbutton, while trimming forward (clockwise) the

minimum load % MLC dial, until the “Min Load Trip”LED turns on. The calibration on the minimum load % MLC

dial where this occurs is the actual % load of the maximum load dial setting being drawn by the motor.

If the control panel-mounted auto/manual selector switch is in the auto position it will have no bearing on

the minimum load reset as this will only be reset manually. SHOULD YOUR APPLICATION REQUIRE AN AUTO-

RESET ON THE MINIMUM LOAD FUNCTION THIS MUST BE SPECIFIED AT THE TIME OF ORDER. The following

red LED trip indicators with clear descritive fault conditions have been mounted on the control panel to assist

maintenance personnel in determining the exact cause of the trip.

* Motor Overload

* Phase Unbalance

* Minimum Load

A green LED is included to indicate the relay healthy status.

KB LV MOTOR PROTECTION RELAY KB LV MOTOR PROTECTION RELAY

8. Dimensional Diagram

9. Electrical Connection Diagram

KB LV MOTOR PROTECTION RELAY KB LV MOTOR PROTECTION RELAY

INPUT CONVERTER

Class : Class 1

Rating : 0,1 VA

Frequency response : 40 – 66 Hz

OVERLOAD TRIP DELAY CURVES

Cold

T TRIP = 15 (35,49) Ln (I/Ie)2- (Ip/Ie)2

((I/Ie )2 - 1)

Hot

T TRIP = 5 (35,49) Ln (I/Ie)2 - (Ip/Ie)2

((I/Ie)2- 1)

Accuracy: ± 5% 1,2 X Ie to 6 X Ie

± 10% 1.01 X Ie to 1,2 X Ie

UNBALANCE / SINGLE PHASING SETTING

Level setting : > 30% Ie

(motor full load)

Trip delay : 5s

FAULT INDICATION

Operation : Latch on trip

Resetting fault indication : Latch

ENVIRONMENTAL SPECIFICATIONS

Reference standards IEC 255

Isolation N/O contact

1 kV for 1 minute To IEC 255-5 C

Isolation separate contacts

1 kV for 1 minute To IEC 255-5 C

Impulse withstand

5 kV To IEC 255-4 EIII

High frequency

IEC 255-4 C III

MAXIMUM LOAD CURRENT SETTING

Level setting accuracy : ± 2%

Linearity : ± 2%

Repeatability : ± 1%

Detection level : ± 2%

Calibration : Amps

OVERLOAD THERMAL LOCK-OUT TIME TO RECOVER

33% CAPACITY

T reset = Curve [2.33 (35,49 x 2) 15 log

(100/70)] – Motor running

T reset = Curve [2.33 (35,49 x 4) 15 log

(100/70)] – Motor standstill

MAIN TRIP RELAY

Current rating : 5 Amps 220

Volt a.c

Configuration : 1n/o + 1n/c

Terminals n/c 7 and 8

: n/o 9 and 10

UNDERLOAD DETECTION

Range : 10 to 100% of maximum

load setting dial

Trip delay : 10 seconds

7. Specifications

This user-friendly relay requires only that you set the motor full load current on the “Max Load Current Amp” dial

to coincide with the protected motor’s full load capability. Prior knowledge of the no load current value of the

protected motor, if known, will be useful. However, it is not necessary, as a procedure will be outlined below to

determine this value.

Note: This relay has a fixed cold thermal curve of 15 seconds which integrates to a 5 second curve as the motor reaches it’s full

thermal capacity. Use of this product on large motors designed for cold thermal curves in excess of 15 seconds will result in over

protection of the motor.

3. Information required for Initial Settings

COLD CURVE

CLASS 15

COLD CURVE

CLASS 5

In a similar fashion, if the motor is run under no load, while consistently pressing the reset button on the control panel it is

possible to accurately determine the % drop in load. This is achieved by setting the“MIN LOAD % MLC AMPS”dial to the minimum

value and then rotating the setting knob slowly clockwise until the MIN LOAD LED lights up. Leave this as a final setting.

No additional features can be set OR disabled on site.

5. Adding or Removing Features on Site

6. Thermal Trip Curves

KB LV MOTOR PROTECTION RELAY KB LV MOTOR PROTECTION RELAY

Ensure that the selected KB relay does in fact cover the full load current range of the protected

motor. Note that the models KB 1; KB 5; KB 10 and KB 25 do not require any additional current

transformers. The relay MUST be installed in the MAIN CIRCUIT of the starter. Being compact in

design the built-in single-turn feed-through primary winding transformers permit the main circuit

cable conductors of up to 7 mm to pass through the protection relay. In the case of the models

KB 50; KB 100 and KB 200 interposing current transformers of 50:5; 100:5 and 200:5

respectively are required. The secondary winding of these interposing current transformers are

then wired through the single-turn feed-through primary winding transformers at the rear of the

relay.

CARE SHOULD BE OBSERVED IN ENSURING THAT THE POLARITY OF THE CURRENT

TRANSFORMERS IS THE SAME FOR EACH PHASE AND THAT THE DIRECTION OF

CURRENT FLOW FROM THE SECONDARY SIDE OF THE TRANSFORMERS IS UNIFORM

FOR ALL PHASES. If this is not done, nuisance unbalance trips will occur.

The KB range of relays is designed for chassis mounting and once installed will require an

auxiliary supply of either 110 OR 220 Volt ac to terminals 12 and 13 OR 11 and 13 as

appropriate.

Connect the N.C contact in series with your trip circuit, (usually the main contactor holding coil)

and, if required, the N.O contact can be used for signalling or control purposes. These are

potential free contacts. Terminals 7, 8 and 9, 10 refers.

Proceed to set the motor full load current on the “MAX LOAD CURRENT AMPS” dial.

Approximate (unless you already know) the percentage drop in load the fully loaded motor will

experience during a no load condition and set that % value on the “MIN LOAD % MLC AMPS”

dial.

Set the auto/manual reset toggle switch to your preferred state after an overload trip condition.

The motor protection relay is now ready.

Tip:

Applicable once the motor is running. When using the KB motor protection relay on an application where the motor load is

relatively constant it may be a good idea to set the “Maximum Load Current Amps” dial to coincide with the actual mechanical

load being drawn by the motor. This can be achieved by holding in the reset button while at the same time slowly turning

counter clockwise on the “MAXIMUM LOAD CURRENT AMPS” dial until the red “Overload” LED lights up. When this point is

reached, you will have established the actual load current being drawn by the protected motor. Now, while still holding down

the reset button gently turn the “Maximum Load Current” dial clockwise until the “overload” LED extinguishes and leave as

a final setting. The result of this setting up method will enhance the protection to the motor in that frequent overload trips

would signal possible bearing degradation which would translate as extra abnormal load to the motor in overcoming additional

frictional forces.

4. Setting up Procedure