Tinker & Rasor AP, AC User Manual

CORROSION MITIGATION INSTRUMENTATION

2828 FM 758, NEW BRAUNFELS, TX 78130 TEL: [phone]

RODUCT INSTRUCTIONS

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MODEL AP/AC

IN-PLANT USE HOLIDAY DETECTOR

1. HOLIDAY DETECTOR FUNCTION
The Tinker & Rasor Model AP/AC In-Plant Holiday Detector is an all-purpose electrical

inspection instrument which maintains a given inspection voltage in spite of the
electrical load on the circuit. It is recommended for use on any pipe diameter as well
as on flat surfaces when such surfaces are coated with a highly electrical resistance
material, and when the surface beneath the coating is electrically conductive. The
detector works equally well on damp or dry surfaces, and is especially desirable where
humid conditions prevail. The instrument can be delivered for operation on either 110v
or 220v AC power.

2. INSTRUCTIONS FOR UNPACKING & INSPECTION
A. Open the shipping carton and make note of the various accessories.

B. INSPECTION should be made upon receipt. If damage has occurred during

shipment, file a claim with the carrier immediately.

C. If it is necessary to contact your supplier or the manufacturer concerning

damaged or missing items, be sure to include the serial number, purchase order
number, and invoice number of the instrument in question.

3. CHECK-OUT INSTRUCTIONS

• Remove all accessories from the shipping carton.

• Make sure that the detector is turned OFF.

• Connect high voltage cable and ground cable to detector (insert and twist

clockwise). Never connect or disconnect the cables when the instrument is
turned on.

• Attach probe handle to voltage cable.

• Attach electrode to the voltage probe assembly and apply to the structure to be

inspected. The electrode should always make intimate contact with the surface
under inspection.

• Plug AC power cord into 110v power supply (220v on specially configured
instruments). See label on outside of case for type.

Web: www.tinker-rasor.com E-mail: [e-mail]

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CORROSION MITIGATION INSTRUMENTATION

2828 FM 758, NEW BRAUNFELS, TX 78130 TEL: [phone]

RODUCT INSTRUCTIONS

P

• The Model AP/AC Holiday Detector is now ready to operate.

• SELECT the HIGH or LOW position. Adjust the voltage setting, using the

digital display for reference.

NOTE: Digital display and actual output may differ as much as 5% due to manufacturer’s
specifications of display.

4. OPERATING METHODS
A good ground return system for both the pipe and the detector will always provide the

best and most reliable inspection. The pipe to be inspected must be grounded from
the bare pipe to earth at some point along the pipe. If individual joints of the pipe are
to be inspected that are not electrically connected, each joint must be grounded. The
speed of the electrode's travel along the pipe should never be excessive, since faulty
inspection may result. Occasional checks of the detector operation should be made,
particularly if no holidays are being found. This can be accomplished by testing for the
spark and signal at the edge of the coating where bare pipe exists or by touching the
probe end to the bare pipe and noting the length of the spark and the signal
effectiveness. If the signal does not occur when the spark discharges from the
electrode into a known holiday, the ground return (i.e. the path between the metallic
pipe and earth and the earth to the ground trail of the detector) is of high resistance.
In this case, a better ground is required and a direct connection between the metal
pipe and the ground wire may be necessary. This type of grounding is extremely
uncommon unless the soil is very dry (if using a grounding rod) or the detectors output
is low.

Correct voltage output for a given thickness of coating has long been a matter of

controversy. However, recent formulas have been suggested which may be used as a
guide for correct peak voltages on various coating thickness. The calculation is as
follows:

V = K √ T

WHERE V = Peak voltage in volts.
T = Thickness of bonded coating in mils (not
including outer wrappers).

K = Constant of 1,250 for coatings over 30 mils

and 525 for fusion bonded epoxy coatings
under 30 mils.

These formulas, when applied to a coating of 3/32” thickness and with a constant of

1,250, would indicate an applied voltage of 12,500 volts peak or a coating of 16 mil

Web: www.tinker-rasor.com E-mail: [e-mail]

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