Standalone OLTC Event Recorder – OTM-X

Ref : OTM-X

The OTM-X is the only standalone recorder using the vibro-acoustic method and motor current testing to detect ONLINE your On-Load Tap Changer’s (OLTC) malfunctions.

Thanks to its technology, it can detect problems such as contact wear, arcing in diverter, arcing in selector, synchronism problem, drive mechanism problem, brake failure etc.
The OTM-X is a special machine, combining a powerful Zensol measurement instrument with a flexible and autonomous computer running the tests.
This combination allows the instrument to be continuously connected to the network. A remote user can thus access data and test plans from anywhere at any time.

The OTM-X can be installed in the OLTC’s control cabinet or in the substation’s premises, for any period of time. No need for an operator to run the tests, the OTM-X is capable of recording unlimited OLTC operations.

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 years.

OpenZen Software

OpenZen is an-all-in-one software that includes all the necessary tools for testing, processing, calculations, analysis and interpretation of results in the field.


  • Autonomous instrument
  • Vibro-acoustic test with high sampling rate (100KHz)
  • Can be used on any type of OLTC or other mechanical equipment
  • Multi-test recorder with 64GB of local storage (or more upon request)
  • 2 years guarantee
Technical description
  • Sampling time: 10 µs to 26 ms
  • Sampling rate: 38Hz to 100KHz
  • Recording time per test: 10 milliseconds to 30 minutes
  • Analog A/D conversion: 16 bits
  • Local storage : 64GB
  • Command Outputs: 2
  • Vibration (Accelerometers) Inputs: 3
  • Multipurpose Analog Inputs (16 bits): 3 or 5
Detailed technical description

Sampling frequency: 38Hz to 100 kHz
Sampling time: 10 microseconds (μs) to 26 milliseconds (ms)
Recording time: 10 milliseconds (ms) to 30 minutes
A/D conversion: 16 bits
Local storage capacity: 64GB/200GB

Works with any analog input
AC or DC signals
Rising or falling edges
Works in noisy environments

Number available: 5
Resolution: 16 bits A/D conversion
Frequency: DC to 200 kHz
Accuracy: +/- 0.3 mV
3 analog inputs with input Voltage: +/- 10 V AC (compatible with all transducers types)
1 analog input for temperature (4-20mA)
1 analog input for position (4-20mA)

Number available: 3
Accelerometer type: ICP
Resolution: 16 bits A/D converter
Frequency: 1 to 20 000 Hz
Signal to noise ratio: better than 80 dB

Number available: 2
Type: solid state, optoisolated
Voltage: 0-200 VDC
Maximum load current: 3.5 Amps
Turn-on time: 75 μs maximum
Turn-off time: 750 μs maximum
Can be independently turned on and off

Uninterrupted control over data, test plans, programs, etc.
Able to perform remotely controlled tests
Data is easily accessed via your network
Completely automated scheduled tasks.

Bandwidth: 10/100 Mb/s
Remote control and recovery of data
Bandwidth: 12/480 MB/s

Current probes
Local memory expansion
USB memory card
USB Bluetooth module
USB Wi-Fi module
BNC to 10-32 cables
BNC to BNC extensions (25 and 50 feet)
Cable reel with four extensions of 50 feet
Accelerometer mounting bases
Watertight case

Rack Mount version
Size: 19” x 3.5” x 18” (48.2 x 8.8 x 45.7 cm)
Weight: 13.2 lb (6 kg)
Portable version
Size: 17” x 16.5” x 10” (43 x 42 x 25.4 cm)
Weight: 25.3 lb (11.5 kg)
Power supply: 100-240V AC (50/60 Hz)
Operating temperature range: 0oC à 50oC (32oF à 122oF)
Storage temperature range: -20oC à 70oC (-4oF à 158oF)


Included with the instrument:

  • OpenZen-OTMX© Software
  • Complete set of manuals
  • Calibration certificate and test reports
  • 1 day training at Zensol’s premises (travel expenses of the attendees not included)
Pdf documentation

Technical specifications

Sharing Knowledge
Customer Downloads
Quick Setup Guide – OTM-X

Learn how to setup your OTM-X

Job aid – OTM-X

Set your OTM-X step by step

If you don’t have the password, please contact us.