Preliminary Instructions; Accessory Description; Introduction - HT Instruments HTFLEX3 5 Series User Manual

1.1.

PRELIMINARY INSTRUCTIONS

The instructions included in this manual are common to the HTFLEX315, HTFLEX335 and
HTFLEX355 flexible clamp models. The "flexible clamp" sentence always refers to any of
the above-mentioned models, unless otherwise specifically indicated. Carefully read the
following recommendations and instructions before using flexible clamp
• Always de-energize circuit under test before installing flexible measuring
heads. Always inspect the connecting cable and the flexible measuring
heads for damage before using this product
• Do not use product if damaged
• Do not use the clamp on non-insulated conductors whose potential to earth
exceeds 1000V
• Do not use the clamp outdoors
• Do not use the clamp at altitudes exceeding 2000m (6.562ft)
• Do not expose the clamp to water splashes
• Avoid shocks and torsion force to the clamp as this can affect the
measurement accuracy
• Do not paint the product
• Do not apply metal labels or any other object over the product as that could
compromise insulation
• Keep the clamp gap perfectly clean
• Should the clamp be unintentionally used without load (not connected to
the measuring instrument), take the clamp off the cable, wait 1 minute
before connecting the clamp to the measuring instrument, then clamp the
cable again

2. ACCESSORY DESCRIPTION

2.1.

INTRODUCTION

The flexible clamp is an innovative current transducer based on the operating principle of
the Rogowski coil combining friendly use with measurement accuracy. The flexible clamp
current probe is similar to a CT or current transformer. The output is an AC voltage which
is, after an integrator circuit, proportional to the AC current value. The output signal is
insulated form the hazardous conductor potentials and is an exact replica of the current
waveform in the conductor. The output signal is available via a 5 pin connector (see Fig. 1
or output signal pin assignment).
CAUTION
Pin 1 → Output signal (+)
Pin 2 → Output signal (-)
Pin 3 → Clamp type detection
Pin 4 → Shield (GND)
Pin 5 → not connected
Fig. 1: Internal connectors scheme
EN - 3
HTFLEX3x5