Rockwell Automation 810 User Manual

INSTRUCTIONS

INVERSE TIME CURRENT RELAYS

BULLETIN

810

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IMPORTANT - Save for future

reference.

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Bulletin 810

with a maximu
continuous

of 60 amperes.

Cross sectional view.

Moving parts are shaded.

DESCRIPTION

rela

OPERATING

COIL

CORE

DASHPOT

SILICONE

FLUID
PISTON

-The Bulletin 810 is a

magnetically operated current relay,
with time delay, for use on AC or DC
applications. It has inverse time-current
characteristics which are dependent.
upon the viscosity of the fluid in the
dashpot. However, unlike thermal re­lays, minimum operating current is inde­pendent of ambient temperature change
or cumulative heating. The relays are
supplied as standard with

a normally

closed (NC) contact and an automatic
reset. Available options are a normally
open (NO) contact, hand reset, and
bifurcated contacts with a clear plastic
(poly-carbonate) cover. Tripping current
and time delay are adjustable.

TIME DELAY TRIP - Current relays are

used when it is desirable to take a motor

off the line in a certain period of time after

a predetermined load condition is
reached. A typical application would be
starting a large motor, where the Bulletin
810 is used to automatically open the
motor starter control circuit if the motor is

CONTACT RATINGS -

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Max AC
Voltage

60 or 50

120
240
480 1.5 10

600 1 12 1 1.2

not up to speed in the maximum accel­eration time allowed. In this and other
applications of the automatic reset type

relay, three wire control must be used,

with a provision for interrupting the cur-

rent through the relay coil immediately
after the relay trips (see typical schema-

tic diagram on page 3). On two wire con-

trol applications such as float switches,
pressure switches or thermostats, a
hand reset type overload relay must be
used to provide this protection to the coil.
The relay can carry its rated continuous
current in the non-tripped position only.

OPERATION -

letin 810 operating coil imparts an elec­tromagnetic force on the movable core.
The vertical position of the core in the
coil is adjustable, thereby providing an

adjustable trip point. When the coil cur-

rent increases to the trip point, the core

raises to operate the contact mecha-

nism. Time delay is provided by a sili-

cone fluid dashpot mounted below the

core and coil assembly. An adjustable

valve in the dashpot piston provides for

time delay adjustment.

AC DC

Maximum Contact Rating Per Pole

NEMA Rating Designation A600

Continuous

Range

Amperes

Hz

Make Break

Carrying
Current

6

3

1;

1

10

Current through the Bul-

NORMAL CURRENT - The electro-

magnetic force caused by normal con­tinuous current through the operating

coil is not great enough to lift the core

and piston. The relay remains

inoperative.

OVERCURRENT- When the current

through the operating coil increases

beyond the trip point, the resultant elec-

tromagnetic force causes the core and

piston to raise. Upward motion is damp­ened through the use of the silicone fluid
dashpot The core rises slowly until the

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-

Voltage

Volt-amperes

Make

Break

7200 720 115-125

7200 720 230-250

7200 720 550-600 0.1

1

7200 1 720

1

Ampere

Rating

00.4

0.2

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piston reaches an increased diameter in
the dashpot, where it is free, to trip the
contact with a quick action. Time and
current required to complete this cycle
are inversely related as shown by the
time-current characteristics curves on
page 2.

RESET - Standard models of the Bulle-

tin 810 are automatically reset as soon

as the current through the coil is inter­rupted or decreased to approximately
20% of the tripping current. The core is
designed to drop quickly, returning the
contacts to their normal position. A
check valve allows the piston to bypass
the fluid in its return to the bottom of the
dashpot. The action of hand reset mod­els differs only in that the contacts do not
reset until a lever on the contact block is
operated. There is no waiting period as
with thermal relays.

EFFECTS OF AMBIENT TEMPERATURE

-

The minimum operating current

(100% on the time-current characteris­tics graph) is independent of ambient
temperature at the relay. However, the

operating time at overcurrent varies

directly to the viscosity of the silicone
fluid. Since the viscosity varies inversely

with ambient temperature, the operating

time is also inversely affected. The time
temperature table shows the correction

factors to be applied to the operating

times for various temperatures.

TIME TEMPERATURE RELATIONSHIP

( +

40°C

Reference)

Ambient

Temperature

Operating Time

Correction Factor

Supersedes Publication 810-5.0, Dated December, 1980

(“C)

2.25 1.80 1.45 1.20 1.0

Publication 810-5.0 - April, 1983

-

+lO"

‘”

+20" +30" +40"

OPERATING CURRENT ADJUSTMENT - stamped on the nameplate. After the

(Not necessary if factory set to user’s

specified value). The minimum operat-

ing current (100% on the time-current

characteristics graph) is adjusted by

changing the vertical position of the core

within the operating coil. Calibration

lines on the core correspond to current

values in the table on Page 3 and

core and dashpot assembly is removed,

the core is turned up or down on the
piston’s threaded stem till the line cor­ responding to the desired operating cur-

rent is in line with the top edge of the

dashpot Currents other than those indi-

cated by the lines are possible by

interpolation.

NOTE: If electrical tests are made of cur-

rent calibrations they should be done
without fluid in the dashpot (clean

and dry.)

SERIES B RELAY OR SERIES B DASHPOTO SERIES A RELAY OR SERIES A DASHPOT 0

ARACTERISTIC AT

+4R"C

000 ’

8001

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0.1 ;

100 200 300 400 500 600

Percent of Minimum Operating Current

10000

TlME-CURRENTCHARACTERlSTICSAT+4O"C

Ez

4000

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'

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1

0.1 '

'

0 100

Percen

t

of Minimum Operating Current

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'

200 300 400 500

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600

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With Series B FluidWith Series B Fluid

Red Fluid

\

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t

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0.2

,>I

0.1 '
0 100 200 300 400 500 600

Percent of Minimum Operating Current

0 Series B Dashpots are identified by the rib along the side of the dashpot. Refer to photo on back page. Series A Dashpots do not have this rib.

1

b-ii

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With Series A Fluid

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'

100 200 300 400 500 600

Percent of Minimum Operating Current

With Series A Fluid

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