Current Switches and Current Transformer Technical Requirements for IAS

This article is about general and technical requirements for Current Switches CS used in Integrated Automation System or Building Automation System.

Current Switches (CS) Technical Requirements for IAS

CURRENT SWITCHES (CS) <Modify as required to match project design>

1. Current Sensing switch shall be self-powered with solid-state circuitry and a dry contact output. Current sensing switch shall accept over current up to twice its trip range. Clamp-On Design Current Operated Switch (for Constant Speed Motor Status Indication):
   1. Range: 5 to 135 amps
   2. Trip Point: Adjustable
   3. Switch: Solid state, normally open, 1.0A @ 30VAC/DC
   4. Lower Frequency Limit: 6 Hz
   5. Trip Indication: LED
   6. Approvals: UL, CSA
   7. Cable Size: 350 MCM
   8. Acceptable Manufacturers: <Confirm list>
      • Honeywell
      • Veris Industries H-908
      • Approved equal
2. Clamp-on Wire Through Current Switch (CS/CR) (for Constant Speed Motors): Same as CS with 24v command relay rated at 5A @ 240 VAC resistive, 3A @ 240 VAC inductive, load control contact power shall be induced from monitored conductor (minimum conductor current required to energize relay 5A, max. rating of 135A).
   1. 1. Acceptable Manufacturers: <Confirm list>
         • Honeywell
         • RE Technologies RCS 1150
         • Veris Industries, Inc. Model # H938
         • Approved equal
      2. Where used for single-phase devices, provide the CS/CR in a self-contained unit in a housing similar with override switch to Kele RIBX.
3. Clamp-On Design Current Operated Switch for Variable Speed Motor Status Indication:
   1. 1. Range: 5 to 135 Amps
      2. Trip Point: Self-calibrating based on VA memory associated with frequency to detect loss of belt with subsequent increase of control output to 60 Hz
      3. Switch: Solid state, normally open, 0.1A @ 30VAC/DC
      4. Frequency Range: 35 to 75 Hz
      5. Trip Indication: LED
      6. Approvals: UL, CSA
      7. Cable Size: 350 MCM
      8. Acceptable Manufacturers: <Confirm list>
         • Honeywell
         • Veris Industries, Inc. H-904
         • Approved equal
      9. Clamp-On Wire Through Current Switch (CS/CR) (for Variable Speed Motors): Same as CS with 24v command relay rated at 5A @ 240 VAC resistive, 3A @ 240 VAC inductive, load control contact power shall be induced from monitored conductor (minimum conductor current required to energize relay 5A, max. rating of 135A).
         1. Acceptable manufacturers: <Confirm list>
            1. Honeywell
            2. Veris Industries, Inc., Model # H934
            3. Approved equal
4. Variable Speed Status: Where current switches are used to sense the status for variable speed devices, the CT shall include on-board VA/Hz memory to allow distinction between a belt break and subsequent ramp up to 60 Hz, versus operation at low speed.  The belt break scenario shall be indicated as a loss of status and the operation at low speed shall indicate normal status.
   1. Acceptable manufacturers: <Confirm list>
      • Honeywell
      • Veris Industries, Inc., Model # H934
      • Approved equal
5. Variable Speed Status: Where current switches are used to sense the status for variable speed devices, the CT shall include on-board VA/Hz memory to allow distinction between a belt break and subsequent ramp up to 60 Hz, versus operation at low speed.  The belt break scenario shall be indicated as a loss of status and the operation at low speed shall indicate normal status.

• CURRENT TRANSFORMERS (CT) <Modify as required to match project design>
  1. The current transformers shall be designed to be installed or removed <by or without> dismantling the primary bus or cables. The transformer shall be of a < solid, split> core design.
     1. The core and windings shall be completely encased in a UL approved thermoplastic rated 94VA. No metal parts shall be exposed other than the terminals.
     2. The current transformers shall meet the following specifications:
        • Frequency Limits: 50 to 400 Hz
        • Insulation: 0.6 KV Class, 10 KV BIL
        • Accuracy: ± .2% at 5.0 to 25.0 VA accuracy class with U.P.F. burden
        • Range <1-10 Amps minimum, 20-200 amps> maximum
        • Trip Point adjustable
        • Output 0-5 VDC
     3. Provide a disconnect switch for each current transformer
     4. Protection: 250 A max current
     5. Acceptable Manufacturers: <Confirm list>
        • Ohio, Semitronics Technologies Inc.
        • Triad Technologies
        • EMON
        • Hawkeye
        • Approved equal