manual for y7- yoke

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MAGNAFLUX A Division Of Illinois Tool Works Inc.

OPERATING MANUAL

FOR MAGNAFLUX YOKE

MODEL: Y (7)

ITW INDIA LTD Plot no. 51 to 52,207&208 Phase-2, IDA, APIIC, Pashammylaram Medak Dist – 502307. Andhra Pradesh. Telephone: 08455-224710 Fax: 08455 – 224709 Website: www.magnaflux.com

MAGNAFLUX, Registered U.S. patent office, a trademark of MAGNAFLUX Corporation applied to its equipment and materials for magnetic particle inspection. Processes and methods used in magnetic particle inspection are covered by various U.S. Letter Patent.

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MAGNAFLUX

A Division Of Illinois Tool Works Inc.

INTRODUCTION This manual contains the necessary information to acquaint the operator of the Y7-Model AC/HWDC Electromagnetic Yoke with its capabilities and operation. The purpose of this manual is to furnish the operator with a functional knowledge of the operation and to make understand the safety precautions which should be applied during operation and maintenance of the equipment. Should unusual situations arise regarding either the operation or maintenance of this equipment, “MAGNAFLUX” staff is available for telephone or mail consultations. In addition, maintenance service is available at the “MAGNAFLUX” Service Department.

PERSONNEL’s FAILING TO COMPLETELY READ AND UNDERSTAND THESE INSTRUCTIONS BEFORE PROCEEDING WITH THE INSTALLATION, OPERATION OR MAINTENANCE OF THIS EQUIPMENT RUNS THE RISK OF INJURY.

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MAGNAFLUX


GENERAL DESCRIPTION The light weight electromagnetic yoke is the ideal tool for detection of surface or subsurface cracks and flaws in any ferromagnetic material. No other low cost, portable equipment offers such versatility in magnetic particle inspection. Fast and simple to operate, it is widely used with either dry or wet method fluorescent or non fluorescent magnetic powders, in the testing of welds, automotive or rail road components, machine parts, steel or grey iron castings, forgings, and in plant inspection maintenance and repair. It is supplied in a “carrying case” for storage and transport. FEATURES Choice of constant level AC or variable intensity pulsed HWDC current for surface

or sub surface flaw detection. Solid state circuitry for infinitely variable (step less), potentiometric adjustment of

DC magnetic field. Articulated legs to suit differing component contours. Inter pole distance

adjustable from 0 to 300 mm. Low power consumption. Current drawn at 220 V, 1 phase supply is only 2

Amperes. Extremely strong and intense magnetic field for superior sensitivity. Portable and light weight. Can be used for AC demagnetization too. No risk of sparking or ‘hot spots’ on the job. No current flows through the component being tested.

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MAGNAFLUX


PRINCIPLE OF OPERATION

When the Yoke is energized by connecting to proper power supply, depressing the “Push to test” switch creates an intense longitudinal magnetic field between the legs. The resultant field can best be described as a multiplicity of invisible lines of force extending across the gap between the legs. As the Yoke is applied to a Ferro magnetic material, the magnetic circuit is closed and the field enters the part making its passage between the legs and at below the surface. A crack across this field cuts the magnetic circuit, the two sides of the crack become opposite poles of magnet and a leakage field occurs in the air above the crack. Magnetic particles sprinkled on the surface are attracted by this leakage field and indicate the location of the flaw. For best results, the Yoke is positioned such that the magnetic field created between the legs is transverse to the direction of suspected cracks.

MAGNETIZING FIELD SELECTION

AC MAGNETIZATION

The induced field is surface field which only detects surface flaws. It is particularly useful for inspecting thick and irregular sections for surface defects. Best results are obtained with dry method.

HWDC (PULSED) MAGNETIZATION

The induced field creates the pulsating magnetic field which penetrates the work piece and detects both surface and sub-surface flaws. The pulsing of the field improves particle mobility & sensitivity and hence, this mode can be used for both dry and wet method. Wet method gives best results.

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MAGNAFLUX


OPERATING INSTRUCTIONS MAGNETIZATION

Adjust the legs to a spacing of 120 mm to 180 mm and place the yoke firmly upon the work piece by securing best possible contact, with the suspected defect transverse to the magnetic field between the legs. With the selector switch in either the AC or the DC position; press the test switch to energize the yoke and lightly dust the magnetic particles (Dry method) or flow the magnetic particle suspension (Wet method) over the area being inspected. As an example, when testing for longitudinal cracks in a “butt weld” the Yoke would be positioned so that the legs straddle the weld. If the direction of a possible defect is not known, two inspections should be made in such area, turning the yoke approximately 90 degrees for second inspection. Use the “AC” mode for surface flaw detection and “DC” for slightly sub-surface inspection.

In the dry method using the power blower bulb, the area between the legs of the Yoke is dusted lightly with MAGNAFLUX POWDER and inspected closely for flaws or other defects. Current should remain “ON” (Continuous method). This process is repeated until the entire area of part is inspected. The “Continuous method” should always be used for maximum sensitivity. Always use the lowest magnetizing current necessary (in DC) to produce distinct indications. Avoid excessively strong fields which may magnetically saturate the test piece and cause “Masking effect” or “Back ground” which will interfere with flaw indication.

DEMAGNETIZATION The Y7- Yoke can usually be used to obtain a satisfactory level of demagnetization. With the equipment in “AC” mode, place the part across the poles and while the current is flowing, slowly withdraw the part from the field to a distance of at least 60 cm before turning off the magnetizing current.

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MAGNAFLUX


TECHNICAL SPECIFICATIONS

Specification

Meets requirements of ASTM E 1444 -05.

Input Supply

220 V ,50 Hz,1 Ph

Input Current

2 Amps

Distance Across Poles

0-300mm

Magnetic Field

AC-Constant level, DC-Pulsed, Infinitely variable

Flux Density

Approx, 10,500 lines of force/cm2 at 100 mm pole spacing.

Pulling Capacity

Approx, 27 Kg (60 Lbs) in DC mode at 100 mm spacing. 5 Kg (11 Lbs) in AC mode at 100 mm spacing.

Yoke Weight

3.5 Kgs Approx.

Duty Cycle

23% (3 Sec On followed by 10 Sec Off)

Controls

On/Off Switch AC/DC Switch DC Field intensity Potentiometer

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MAGNAFLUX


MAINTENANCE

A periodic visual inspection of the interior electrical components is highly recommended. Such an inspection can preclude operational malfunctions and components failure. Disconnect the supply before gaining access to the interior of the magnetic yoke. Check all the wiring for the discoloration, burnt insulation and loose

connections. Ensure the cables are free from cuts which expose the wiring.

Prevent the yoke body and its interior from wet particles and liquids. Liquid baths or wet magnetic particles if peeped inside the body can damage the yoke components and can affect its working efficiency.

The equipment should be cleaned with a soft brush to loosen stubborn particles with care being exercised to avoid damaging delicate electrical leads.

After every six months yokes should be checked for its pulling capacity. It should lift minimum 4.5 KG at 100 mm spacing for A.C. selection and 22.5 KG at 100 mm spacing for D.C. selection.

When equipment is not in use keep it at safe place, probably in its carrying case.

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MAGNAFLUX


PRECAUTIONS

Do not operate the Y7 yoke for longer than 3 seconds ON followed by 10

seconds OFF, i.e. 23% duty cycle. DO NOT energize the Yoke for more than the duty cycle – If the yoke is too hot

to hold in the bare hand it is a sign that the duty cycle has been exceeded. Wait for the yoke to cool before continuing.

DO NOT connect the Yoke to a battery for portable work.

DO NOT change the AC / DC selector switch while the unit is energized.

Ensure that there is firm contact between test piece and Yoke legs for better

indications of the defects and less noise. DO NOT open the yoke handle and change any settings on the PCB.

DO NOT drop the Yoke from a height or subject the handle to any service

impact. Ensure that Yoke is connected to ‘earth’ through proper 3 pin plug for operator

safety.

Do not replace any parts with other than those recommended by MAGNAFLUX.

Do not smoke while performing NDT.

Do not use the supply cable to pull, lift or carry the equipment.

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MAGNAFLUX


TROUBLE SHOOTING

Problem

Possible Causes

a) Unit does not operate in

AC/DC Mode.

1) Defective push button AC Switch. 2) Open wire in power cord or plug. 3) Open coil wire.

b) Unit will not run off

1) Fused “Push-to-test” switch

2) Jammed “Push-to-test” switch.

c) Unit over heats

1) Defective circuit board

2) Shorted coil 3) Enhanced Duty Cycle

d) Unit does not operate in AC

1) AC / DC switch contacts open

2) Open wires in PCB or wiring

e) There is no control in

DC Mode

1)Faulty level control potentiometer

Do not replace any parts with other than those recommended by Magnaflux.

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MAGNAFLUX


SPARE PARTS LIST FOR Y7-YOKE

S.NO.

PART NAME

PART NO.

1

PCB ASSEMBLY

F03033

2

PUSH TO ON SWITCH

F03093

3

AC / DC SWITCH

F03094

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MAGNAFLUX


Yoke

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MAGNAFLUX


OTHER YOKE MODELS

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MAGNAFLUX


WIRING DIAGRAM FOR Y7-YOKE

manual for y7- yoke

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