AMETEK 1500 User Manual
INSTALLATION & SERVICE MANUAL
A
1500 Induction Control Relays
Principle of Operation
A B/W fl oatless liquid level control system consists of a relay
of the proper type, a holder designed to support one or more
electrodes or probes in the liquid container, and the corrosion
resistant electrodes themselves. In as much as all B/W induction
relays are quite similar differing only in contact arrangement, the
following description of how a 1500-C Relay functions on a
pump down control application will serve to explain the design,
construction, and operating principles for the entire line.
As shown in diagrams below, the laminated core of the relay is
shaped. The primary coil is assembled to the upper bar of the
core, and the secondary coil for the electrode is placed on the
lower bar. An armature located below the legs of the
connected to an insulated arm carrying the movable contacts.
When the armature is raised, these contacts close or open
the motor and electrode circuits, depending upon whether the
contacts are normally open or closed. (Contacts shown normally
open in this example).
core is
1500 Series
When a source of alternating current is connected to the primary
coil at terminals 3 and 4, the primary coil sets up a magnetic
fl ux which circulates through the shortest path following the lines
of least resistance. As shown in Figure 1, this is through the
lower bar of the laminated core on which the secondary coil is
mounted. This magnetic fl ux induces a voltage in the secondary
or electrode circuit coil. No current can fl ow in this coil, however,
until the circuit is completed between the electrodes. Thus, the
electrode circuit voltage being generated within the relay has no
connection with the power line.
The B/W 1500 induction relay utilizes the liquid as an electrical
conductor to complete the secondary circuit between the upper
and lower electrodes. Thus, when the liquid contacts the upper
electrode, the resulting fl ow of current in this circuit sets up a
bucking action in the lower bar of the core. This action tends
to divert lines of magnetic force to the core legs and sets up an
attraction that pulls the armature in to contact with the legs, as
shown in Figure 2. This armature movement closes the electrode
and load contacts.
The lower contacts on 1500-C Relays (terminals 9 and 10)
connect the secondary circuit to ground when liquid contacts
the upper electrode and act as a holding circuit to maintain the
relay in its closed position until the liquid falls below the lower
electrode. This holding circuit provides control of the relay over
any desired range in the liquid level, depending on the distance
between the upper and lower electrodes.
The fl ow of current through the low energy secondary circuit
is very small and varies with the voltage of the secondary coil.
The secondary coil is selected to operate over the resistance
of the liquid being controlled. Accordingly, since there is a wide
range of secondary coils from which to choose, it is important
that complete information regarding the nature of the liquid be
furnished when ordering B/W induction relays.
1500C Relay Used for Pump Down Control
.C. LINE
FLUX
GROUND:
3
5
7
9
ARMATURE
A GOOD DEPENDABLE
GROUND RETURN
CONNECTION TO THE
LIQUID IS REQUIRED
Figure 1 - Secondary coil circuit open; armature down. Figure 2 - Secondary coil circuit closed; armature up.
4
6
8
10
TO MOTOR STARTER
PUMP START
ELECTRODE
PUMP STOP
ELECTRODE
A.C. LINE
FLUX
GROUND:
3
5
7
9
ARMATURE
A GOOD DEPENDABLE
GROUND RETURN
CONNECTION TO THE
LIQUID IS REQUIRED
10
4
6
8
TO MOTOR STARTER
PUMP START
ELECTRODE
PUMP STOP
ELECTRODE
1
Installation Instructions
Relay: Install relay in level upright position. Connect wires
from AC supply to terminals #3 and #4 on relay. Make sure
power is of same rated voltage and frequency as shown
for connection to primary coil on relay data plate. Relays
draw 9 volt amperes.
Electrodes: Install electrodes in tank or well by
suspending them vertically from an electrode holder or
some other suspending means. One electrode should be
set at desired start level and one at desired stop level. For
sewage or surface drainage sumps, make sure electrodes
are hung far enough apart so that foreign matter fl oating
on water cannot foul electrodes. Size 18 or larger Type TW
or THW wire is recommended for connection to the relay.
Field Replaceable and Convertible Contacts
The Series 1500 Induction Relay provides circuit versatility by offering
a contact kit that allows fi eld conversions from N.O. to N.C. or N.C.
to N.O. contact arrangements. This option also allows you to add or
replace contacts (up to 3 per relay) as required for expansion of your
liquid level control needs.
CAUTION - Although the electrodes are connected
to a low energy secondary coil output which has
inherently low current, there may be up to 800 volts
between the electrodes or from an electrode to
ground. (See Secondary Coil Table.) Thus wiring and
electrodes should be installed to protect personnel
from accidental contact.
Ground: A system ground return circuit is required from the
indicated relay terminal to the liquid in order to complete
the secondary circuit of relay. Conduit should not be
used. Instead, connection should be made directly to
uninsulated metal tank, or to metal pipe connected to tank
below normal low liquid level. In wells, connect ground
to pump or metallic water pipe. For concrete, wood, or
insulated tanks, use an extra common electrode extending
slightly below the longest operating electrode.
Secondary Coil: Because the secondary voltage on all B/
W relays is an induced voltage generated within the relay
itself, the secondary coil should never be connected to any
source of power. Voltage of the secondary coil installed on
a given relay is determined by conductivity of liquid to be
controlled.
Remove cover plate and armature
For a N.O. contact,
install the moveable
contact in the
armature assembly
facing toward the top
of the relay. (away
from the armature)
Contact Kit Part No. 15-000001
N.O. Contact N.C. Contact
For a N.O. contact, install the
stationary contacts facing toward
the bottom of the relay (toward the
armature).
For a N.C. contact,
install the moveable
contact in the
N.O.
armature assembly
facing toward
the bottom of the
N.O.
relay. (toward the
armature).
N.C.
For a N.C. contact, install the
stationary contacts facing in
toward the top of the relay (away
from the armature).
Load Connections: B/W relays are two-wire control
devices having load contacts rated at 1 hp., single-phase,
115 or 230 volts AC or standard duty pilot rating up to 600
volts AC. In operation, load contacts act as a switch to
open or close a circuit. Connecting them to an external
load does not introduce a source of alternating current into
the circuit.
Accordingly, in making connections for direct operation of
single-phase loads within rated capacity of relay, power
connections must be made as shown in relay wiring
diagram.
To operate higher rated single-phase loads or threephase loads, a magnetic starter must be used. In making
connections to motor starter, follow directions given on
the starter wiring diagram for connecting two-wire control
devices.
2
TOP CONTACT
TERMINALS 1 & 2
MIDDLE CONTACT
TERMINALS 5 & 6
BOTTOM CONTACT
TERMINALS 9 & 10
CONTACT ARRANGEMENT CODE
A B C D E F G H J
1 N.O.
1 N.C.
2 N.O.
1 N.O.
1 N.C.
2 N.C.
3 N.O.
2 N.O.
1 N.C.
1 N.O.
2 N.C.
3 N.C.
1
3
LINE VOLTAGE
5
Clawson, Michigan 48017 U.S.A.
SECONDARY
7
1500-
9
R
B/W CONTROLS
50/60 Hz
VOLTS
2
4
6
R
8
10
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