Holiday Detector Model M1/AC


Holiday Detector Model M1/AC

Tinker & Rasor Hoilday Detector Model M1/AC

Model M1/AC

Holiday Detector for In-Plant Use

General Description

The same features found in the Model M-1 are also found in the Model M1/AC. The M1/AC is powered by 115 volt, 60 Hz, A.C. and produces a regulated output voltage of 67.5 volts D.C. This allows for 24 hour “in-plant” operation without down time for battery changes. The M1/AC is used extensively in rebar coating and other production type coating plants.

The Model M1/AC Holiday Detector is a highly sensitive electrical instrument, designed to locate holidays (pin holes, voids, etc.) in thin film coatings of relatively high electrical resistance, when such films are applied to the surface of material of low electrical resistance. In applications such as painted metal surfaces, the M1/AC Holiday Detector will locate these points very accurately and will indicate their existence with an audible bell signal. This method of electrical inspection of thin film is considered a non-destructive test with an applied voltage of 67-1/2Volts D.C. to the coated surface.

The detector operates from 110/120 volt 50/60 cycle A.C. line current. The electrical design of the M1/AC Holiday Detector utilizes a sensitive relay which is activated by a voltage regulated, solid state power supply. When a current of approximately 750 micro-amperes flows through the system the relay closes and actuates the signal bell.

The electrical components are housed in an anodized aluminum case for maximum protection. The detector is equipped with an on/off switch, pilot light, wand terminal, ground terminal, fuse receptacle, A.C. cord, and signal bell.

The exploring electrode consists of cellulose sponge attached by the metal clamp to a phenolic wand handle and wand cable. The ground cable consists of a cable with direct connect clamp.


  • Regulated inspection voltage.
  • Instant calibration verification.
  • Non-destructive detector metal case.
  • Low applied of no more than 67.5 volts.

The Model M1/AC Holiday Detector consists of:

  • Detector Unit. Input 110/120 VAC, 50/60 Hz. Output 67.5 VDC.
  • Wand with 18″ phenolic handle, clamp and 15-foot cable.Longer wand handle or cable available at extra cost.
  • Cellulose sponge electrode 2″ x 2″ x 7″.
  • Ground wire, 15-foot cable with clamp.
  • Set of operating instructions.