On Load Tap Changer Analyzer – TAP-4-PLUS

The Tap-4-PLUS is the newest instrument by Zensol for OLTC testing. It has 2 more analog inputs than the TAP-4. The TAP-4-PLUS with the TAP-DRM accessory can perform dynamic resistance, vibration, and motor current recordings at the same time. Doing so will allow you to easily understand the vibration impacts.

Like the TAP-4, the TAP-4-PLUS can test all types of OLTC: resistor, reactor, or vacuum, of any brands (Maschinenfabrik Reinhausen (MR), ABB, Federal Pioneer, Ferranti, etc.).


  • Able to perform dynamic resistance testing
  • Vibro-acoustic test with high frequency (100KHz)
  • 3 tests in 1 (DRM, vibro-acoustic, and motor current)
  • Can be used with all types of OLTCs
  • 2 years warranty
Sampling frequency100 kHz
Sampling time microseconds (μs)10 μs
Analog inputs (-10V to +10V)3
Accelerometer inputs3
External TriggerYES
Dynamic Resistance capability (DRM)YES
Recording timeUnlimited