On Load Tap Changer Analyzer – TAP4

Ref : TAP-4

The TAP-4 is the first instrument to use vibro-acoustic measurement to perform tests on On-Load Tap Changers (OLTC).

Thanks to its innovative method based on recording and analysis of vibro-acoustic signals, the TAP-4, like a stethoscope will perform a complete check-up of the internal mechanical state of the OLTC without opening it!
It is able to detect a great variety of mechanical malfunctions : contact wear, arcing in diverter, arcing in selector, synchronism problem, drive mechanism problem, brake failure etc.

The TAP-4 is a universal device, it adapts itself to any type of transformers: MR Reinhausen, ABB, Ferranti, Federal Pioneer and others.

The instrument is used with a current sensor clamp and 1 to 3 accelerometers, therefore you can personalize it according to your needs. Also, its technology has been approved by Hydro-Québec and recognized by international associations such as IEEE and the Cigré.

We also pay strong attention to the high quality of our products so that they can resist impacts and extreme conditions (-20°C to 70°C) with a life expectancy that exceeds 15 proved years.

OpenZen TAP Software

The Tap-4 is driven with a powerful and user-friendly software, OpenZen-TAP, to record and analyze the OLTC events.

The software integrates many calculation and graphic functions to be able to build tests references and tests recordings for comparison analysis.


  • Database with over 70 OLTC models
  • Spots out malfunctions only detectable with a high sampling vibration (100KHz)
  • Can be used on any type of transformers
  • Efficiency in testing due to On-Line/Off-Line operation and non-intrusive methods
  • 2 years guarantee
Summary of technical description
  • Resolution: 16 bits conversion (+/-LSB)
  • Voltage range: +/- 10 V
  • Frequency range: DC to 300 kHz
  • Signal to noise ratio: Better than 80 dB
  • Sampling time: 10 μs
  • Sampling frequency: 100 kHz
  • Recording time: Unlimited
Detailed technical description

Sampling frequency: 100 kHz
Sampling time: 10 microseconds (μs)
Recording time: Unlimited
Accuracy: +/- 1 mV
Signal to noise ratio: better than 80 dB
Instant data transfer to PC via USB link.
Self-diagnostic function for AC clamp.
Self-diagnostic function for accelerometers.
The OpenZen software gives complete control over the system.

Accelerometer type: ICP
Sensitivity: 100 mV/g
Range: ±50g
Frequency range: 1 to 20 000 Hz
Drive current: 4 to 20 mA

Resolution: 16 bits conversion
Voltage range: +/- 10 V
Frequency range: DC to 200 kHz
Signal to noise ratio: better than 80 dB

Size: 12.9” x 13.7” x 7” (33 x 35 x 18 cm)
Weight: 15.43 lb (7 kg)
Power supply: 100-240V AC (50/60 Hz)
Operating temperature range: 0oC to 50oC (32oF to 122oF)
Storage temperature range: -20oC to 70oC (-4oF to 158oF)

Able to sustain shocks and falls without damage
Case made of reinforced polyethylene with molded reinforcements for maximum protection
No fragile components such as integrated printers, screens, or keyboards.

OpenZen software
Complete set of manuals
USB cable
Ground cable
Power cable
2 years warranty
Calibration certificate and test reports.

Accelerometer and AC or AC/DC current clamp
Accelerometer cable (10-32 to BNC)
BNC to BNC cables (10 to 50 feet)
BNC-BNC extensions
Carrying cases for accessories
Accelerometer mounting bases

PDF documentation

Technical specifications 


Shandong EPRI and Hydro-Québec approval (HQ approval)

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