ABB SV-1 Instruction Leaflet - Page 3

Browse online or download pdf Instruction Leaflet for Relays ABB SV-1. ABB SV-1 20 pages. Instantaneous current and instantaneous voltage relays

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SC, SC-1, SV and SV-1 Relay

with tapped coils, as there is not sufficient space for

marking a scale for each tap. However, the scale

plate is supplied in order that a customer may mark

on it the individual relay setting or settings if desired.

3.0 INSTALLATION

The relays should be mounted on switchboard pan-

els or their equivalent in a location free from dirt,

moisture, excessive vibration, and heat. Mount the

relay vertically by means of the four mounting holes

on the flange for semi-flush or by means of the rear

mounting stud or studs for projection mounting.

Either a mounting stud or the mounting screws may

be utilized for grounding the relay. The electrical con-

nections may be made directly to the terminals by

means of screws for steel panel mounting or to the

terminal studs furnished with the relay for thick panel

mounting. The terminal studs may be easily removed

or inserted by locking two nuts on the stud and then

turning the proper nut with a wrench.

For detailed FT case information refer to I.L. 41-076.

4.0 ADJUSTMENTS AND MAINTE-

NANCE

The proper adjustments to insure correct operation of

this relay have been made at the factory and should

not be disturbed after receipt by the customer. If the

adjustments have been changed, the relay taken

apart for repairs, or if it is desired to check the adjust-

ments at regular maintenance periods, the instruc-

tions below should be followed.

All contacts should be cleaned periodically. A contact

burnisher Style 182A836H01 is recommended for

this purpose. The use of abrasive material for clean-

ing contacts is not recommended, because of the

danger of embedding small particles in the face of

the soft silver and thus impairing the contact.

Several factors may affect the dropout ratio of the

relay. Whatever affects the ratio does so because

either the dropout or pickup or both are affected.

Obviously, incorrect assembly or interchange of

parts, such as the use of the SC plunger with the SV

core tube, will alter the electrical characteristics.

However, the factor most likely to be encountered in

service is friction. This may be due to dirt or foreign

material between the plunger shaft and its bearings,

to excessive pressure of the indicator screen on the

indicator, or to leads so mis-shaped that they tend to

rotate or tilt the moving contact insulation plate with

appreciable force.

In order to remove the plunger and shaft assembly, it

is necessary to remove the setscrew and nut at the

top of the shaft. The spool-shaped bushing assem-

bled on the upper end of the plunger shaft has a por-

tion of its center section machined off so that the

shaft is exposed at this point and can be prevented

from turning by gripping shaft and bushing with a pair

of long-nose pliers while removing the set screw and

nut. Then by pressing down with the fingers on the

upper end of the shaft, the lower split sleeve which

retains the lower bearing will be forced out of the

threaded tube, the bearing will drop out freely, and

the upper split sleeve will be forced out far enough to

permit grasping it for removal. The shaft and plunger

assembly then can be removed.

The shaft and plunger assembly should be handled

carefully to avoid bending the shaft or damaging the

bearing surfaces. The shaft should never be gripped

on it upper bearing surface, below the spool-shaped

bushing, when loosening the nut and setscrew, as

this would almost certainly damage the bearing sur-

face. The shaft bearing surfaces should not be

cleaned or polished with any abrasive material, as

the abrasive particles might become imbedded in the

shaft and cause difficulty later. The plunger shaft and

bearings may be cleaned by wiping them carefully

with a clean, lint-less cloth. Use no lubricant on the

plunger shaft or bearings when re-assembling the

relay, since this will eventually become gummy and

prevent proper operation. It is recommended that the

shaft be cleaned at intervals of approximately two

years. When replacing the lower bearing and the split

sleeves, the shorter sleeve (assembled below the

bearing) should be pushed in until it is flush with the

end of the threaded tube.

The mounting holes in the operation indicator screen

are slotted so that its position can be adjusted. For

relays in which the moving contacts are not latched

in the operated position, the screen should be so

located that the indicator positively enters the screen

opening when the contacts barely touch. For latch-

type relays, the screen should be so located that

good contact is still obtained when the relay is de-

I.L. 41-766.1N