Western Instruments WE-7 User manual

WE-7 Operating Instructions
1
26509 Township Road 543 Phone: [phone]
Sturgeon County, Alberta Fax: [phone]
T8T 1M1 E-mail: [e-mail]
Web: www.westerninstruments.com
Operating Instructions
WE-7
Compact AC/DC Yoke
Established 1965

WE-7 Operating Instructions
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The WE-7 allows the Operator to induce an AC or a pulsed DC field into the
ferrous material being tested. The device should be utilized within the
parameters set by the operational specifications within this guide.
1. Push Button Switch – The Lycon (#11-304) Micro-Switch is the same
style of switch used in all Standard Yokes (WE-Series and Competitive units).
This style of switch has no grounding provision, so care must be taken by the
operator while performing Wet Method Inspection. The Switch Housings on
WE-Series Products were designed for comfort and safety. While depressed,
the switch delivers power (AC) to the coil encapsulated in the Yoke housing.
Review the instructions in this guide, for switch replacement.
2. Slip-In Switch Cover – The Slip-In Switch Cover is exclusive to WE-
Series Yokes. To remove the cover, simply pinch the cover and pull it out.
While the Slip-In Switch Cover provides superior resistance to moisture
ingress, than mechanically fastened switch membranes, it must be regularly
removed to clean the Switch and Housing, during wet method inspection,
This cleaning will aid in the avoidance of operator shocks.
Push Button
Switch
Target Area
Junction End Cap
AC/DC Selection
Switch & DC
Intensity Knob.
Pole Pieces
Crack Orientation
Top
Bottom
Wide Side of Switch Cover (Right).
Top
Bottom
Helping in Switch Cover
Top Bottom Right Left

WE-7 Operating Instructions
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The cover is designed to fit best into the cast groove with the wide side to the
right (as illustrated) of the Yoke body. Furthermore, the feeler button, on the
raised portion of the switch cover is farthest away from the switch connections.
To insert the Switch Cover, bend the cover longitudinally, and slip the top
of the cover into the grove. Use a small screwdriver to help the bottom of the
cover into the groove after the top is in place. During factory assembly, the cover
is slightly lubricated/moistened. Ensure the lubricant does not dry, and create a
vacuum in the Switch Cavity, which causes the Switch to stick.
3. Field Selection – The WE-7 provides the operator with either an AC or DC
Field, simply by changing the position of the AC/DC switch on the Control Panel.
While in DC mode, the Field Intensity is Infinitely Variable, with the use of the
Intensity Knob, which is also located on the Control Panel. An illustration of the
Control Panel is show bellow.
DO NOT CHANGE THE FIELD WITH THE PUSH BUTTON DEPRESSED
Mounted to the rear of the Control Panel, and inside the Junction End Cap, are
the Control Board and Heat Sink. To remove the Control Panel and Junction
End Cap, Fasteners #1 and #2 are the only ones to be removed. The Control
Printed Circuit Board directs AC voltage directly into the Yoke’s Coil (AC Mode)
or Converts it to DC and again directs it into the Coil (DC Mode). The DC
Intensity Controls are contained on the same Printed Circuit Board, and adjusts
the DC Voltage and thus the lifting power of the Yoke.
Adjusting the DC Intensity Knob while the Yoke is activated is completely
acceptable. However, the Field Selection Switch (AC/DC) should not be touched
DC Intensity Knob
AC – Position
DC – Position
Junction End Cap
Identification
Information Power Cord &
Strain Relief
Fastener #1
Fastener #2

WE-7 Operating Instructions
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while Yoke is turned on. If the Field Selection Switch is changed when the Yoke
is on, an overload may occur. When overloaded, the Control Printed Circuit
Board my fail, resulting in a partial or complete failure to this component, and/or
the electrical breaker the Yoke is supplied from (Mains) may be tripped.
DO NOT CHANGE THE FIELD WITH THE PUSH BUTTON DEPRESSED.
4. Operational Parameters –The Operational Parameters or Duty Cycle for
the WE-7 operation is set to avoid damage to the internal coil or the Control
Printed Circuit Board, and must be observed.
AC Operation: It is recommended that the operator does not keep the Yoke on
for more than ½ hour at a time, as the Yoke housing may get too warm to hold.
However, the basic design of any Yoke inherently produces heat. Typical
operation is 5 - 15 seconds on, while applying inspection media, followed by 5 -
15 seconds off repositioning the yoke to the target area.
DC Operation: At the maximum setting, the Yoke should not be kept on for
more than 10 minutes at a time, and should be followed by an equal cool down
time. Typical operation is 5 - 15 seconds on, while applying inspection media,
followed by 5 - 15 seconds off repositioning the yoke to the target area. In this
typical operation the unit can be operated for extended periods of time, however
the Yoke housing may get to warm to hold.
If the Yoke is used for prolonged periods of time of continuous cycling, such as 2
to 3 hours in AC mode or 60 to 90 minutes in DC mode, as outline above, the
Yoke may get hot. If the WE-7 is used in this manner the operator must provide
time for a sufficient cooling period, or components in the Electronic Control
Module may fail.
Do not change the FIELD SETTING while the unit is activated.
5. Field Characteristics
AC Field – AC Magnetic Fields are sensitive to surface and near surface defects
due to the ‘Skin Effect’ as the field travels from one Pole Piece to another. The
Inspection Media (Dry Powder or Wet Method Particles) has a tendency to
migrate toward interruptions (or defects) in the field. The direction and intensity
of an AC Field, by it’s nature, alternates causing high particle mobility, so defects
tend to be revealed immediately.
.
DC Field – The Pulsed DC Magnetic Field is stronger than an AC Field and
tends to penetrate the work piece more deeply, however DC is still sensitive to
surface defects. Inspection media tends to adhere to the entire target area of the
work piece, due to the reduced particle mobility, and may need to be ‘blown off’
to fully reveal an indication. The intensity of a DC Field, by it’s nature, is fixed but
the Yoke does Pulse the field providing some stimulus for the particles to migrate
to defects.

WE-7 Operating Instructions
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Demagnetization – Small Parts may be demagnetized by positioning the contact
surfaces of the Pole Pieces together, activating an AC Field and pass the part
through the opening formed between the Legs and Yoke Housing. Larger Work
Pieces can be demagnetized by placing the Yoke on the surface, in a similar
manner used during inspection, activating an AC Field and pull the Yoke off the
surface. The work piece can be tested with a Magnetic Field Indicator, such as
the W-Series W-PT, to ensure it is fully demagnetized.
6. Operation:
Select the desired field on the WE-7, and position the Pole Pieces (Feet) on the
work piece. The area between the pole pieces is your target area, which also
extends laterally out, approximately 1.5” (38mm), from either edge of the pole
pieces. The Field will expose defects that are transverse to the centerline
between the Pole Pieces. The Pole Pieces should be positioned, so that as
much of their contact surface as possible is in contact with the work piece. The
Yoke is then energized, by pressing the Push Button Switch, and Magnetic
particles are applied. Dry Method Particles are dusted between the Pole Pieces
and over the target area, while Wet Method Particles are sprayed in a similar
manner.
The area is then inspected visually for a collection of Particles around defects. A
Black Light is used to aid visual inspection when Fluorescent Particles are used.
Indications found with Dry Powder and an AC Field will tend to form immediately,
and will take slightly longer with Wet Method Particles. While using a DC Field,
Dry Method particles behave similar to AC, but Wet Method Particles tend to flow
far slower requiring a longer activation time. If the typical direction of defects is
not known, rotate the Yoke through 90º and repeat the inspection of the target
area. Follow the Operational Parameters outlined in these instructions, and
again;
Do not change the FIELD SETTING while the unit is activated.
7. Maintenance
After extended use the Yoke should be cleaned with a mild soap solution and
thoroughly dried. The unit should be visually inspected for any damage that
could cause harm to the operator, or the material being inspected. Special
attention should be paid to the Push Button Switch Cover, to ensure it is fully
inserted to the groove cast in the Switch Cavity. Furthermore, the Power Plug,
Power Cord, Strain Relief, and the Junction End Cap should be in a good state of
repair. Before performing maintenance or the Yoke should be disconnected from
any power source, with safe industrial practices employed. Any potential
problems to these assemblies must be reported to the Distributor or Western
Instruments for instructions on corrective action.
If there is a failure in the Control Printed Circuit Board, the Control Panel may be
removed. Repairs to this component are not a field fix (as illustrated bellow),
even if an extra Board is on hand. Replacement requires fine tools, and

WE-7 Operating Instructions
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furthermore there are adjustments on the Board that require a Clip-on Amp Meter
and a Digital Multimeter.
Whether industrial specifications are being observed or not, the Yoke should be
tested periodically, using a certified Pull Test Bar such as the W-Series W-PT,
to ensure it continues to lift the specified amount of weight. If the unit fails such a
test, first inspect the Pole Pieces to ensure they fully contact the test weight. If
the unit continues to fail, contact the Distributor or Western Instruments for
instructions on corrective action.
Wiring
W-Series 230 Volt Models, are designated by a “K” placed after the Serial
Number and the Model number (e.g. WE-7K), are shipped without an AC Power
Plug as there is no international standardization. When installing an AC Power
Plug onto the AWG 18-3 Power Cord, the following is the identity of the 3 Color
Coded Conductors;
•Green – Ground
•White - Neutral
•Black – Live
Care must be taken to insure the proper installation of an AC Power Plug, and
if there is any question, contact your distributor or Western Instruments. If an
AC Plug in not installed before use, any warranty is void.
8. Warranty
Western Instruments warrants its products, against defects in materials and
workmanship for a period of 1year from receipt by the end user. If Western
Instruments receives notice of such defects during the warranty period, Western
Instruments will either, at it’s option, repair, replace, or condemn products that
prove to be defective. Consumable items, such as Batteries are warranted for 30
days, from receipt by the end user.
Any warranty is void if the unit has been modified in any way, or if it has been
repaired by an unauthorized agency. The end user agrees that any equipment’s
disposition, when returned for warranty work, is at the full discretion of Western
Instruments as to whether a claim is under warranty, or due to misuse. Western
Wire Identification;
•Blue - Sensing
•Orange - Common
•Black - Live
Control Printed
C
ir
cu
i
t
B
oa
r
d
DC Intensity Pot
Polarity Switch
Control Panel

WE-7 Operating Instructions
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Instruments warranty shall overlook normal wear, however does not include
operation outside the environmental specification of the product. All warranty
work is FOB Western Instruments, and any returned units shall include a written
description, by the end user, of the fault.
Western Instruments makes no other warranty, either expressed or implied, with
respect to this product. Western Instruments specifically disclaims any liability
arising form the use of this equipment. For the correct use of the product, refer
to the Operating Instructions, furthermore we recommend instructional training to
CGSB, ASNT, or other regulatory authority qualifications. Western Instruments
highly recommends the end user exercise all possible safety precautions,
including use of protective equipment, while operating this or other industrial
equipment.
Specifications:
Models WE-7 or WE-7K
Voltage: 115VAC or 230VAC
Frequency: 50 or 60 Hz
Current: 4 Amps @ 115 Volts, 2 Amps @ 230 Volts
Controls: Switch, DC via SCR and Phase Angle Control
Capacity: AC - <10 Pounds (4.6 kg)
DC - <50 Pounds (23 kg)
Pole Spacing: 0 – 11” (0 – 280mm)
Pole Cross Section 1” (25mm)
Weight: 7.5 Pounds (3.4 kg)
WesternInstrumentsInc.
WesternInstrumentsInc.WesternInstrumentsInc.
WesternInstrumentsInc.
Phone: [phone]
Fax: [phone]
E-mail: [e-mail] Web: www.westerninstruments.com