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Inspire have redesigned the classic demonstration apparatus to address the safety issues in the conventional apparatus. The conventional design always had the chance to generate lethal voltage if a wrong primary-secondary combination of coils were used. Using the purpose designed power supply, no voltage greater than 25V ac can be experienced in whatever combination of primary – secondary coils the user selects. Also, the wings of the specially designed coils prevent any wrong combination to generate a high secondary voltage. The 25 V ac output terminal of the power supply cannot be connected across the ordinary coils to make step-up or step-down transformer and hence safe. Only specially designed coils with special connectors joins to the 25V ac terminal.


Exp–1 AC induction: Dependence of Induced Voltage On Coil Core.

Exp–2 Relationship between Transformer Input And Output Voltage Waveforms.

Exp–3 Dependence of Transformer Output Voltage on The Turns Ratio of the Transformer.

Exp–4 Variation of Transformer Primary Current with Secondary Current.

Exp–5 Transformer Efficiency and its Dependence on Load.

Exp–6 Moving Iron Meter Model.

Exp–7 Determination of Coil Induction.

Exp–8 Half-wave Rectification

Exp–9 Full-wave Rectification with Centre-tapped Transformer.

Exp–10 Full-wave Rectification with Diode-bridged Transformer.

Exp–11 To Produce a Low Voltage but Higher Current to Melt a Nail.

Exp–12 Demonstration of Induction Furnace.

Exp–13 Demonstration of Thomson’s Jumping Ring Experiment.

Exp–14 Demonstration of Eddy Current Braking.

Exp–15 Demonstration of Shaded Pole Induction Motor.

Demountable Transformer Kit


Cat. No.Item NameQty.
C15048Clamp base1
C15043300 Turns’ Coil1
C15044600 Turns’ coil2
C15045900 Turns’ coil1
C150471800 Turns’ coil1
C150461200 Turns’ coil with centre-tapping [0 – 600 -1200]1
SA719100 Turns’ coil with wings1
SA720300 Turns’ coil with wings1
C8470U & I Core, section 32X25mm1
SN200Connecting Leads 50cm8
SA722Demountable Transformer Power Supply1
CB397Quadrant Shaped Plane Plate1
CB398Quadrant Shaped Slotted Plate1
CB392Aluminium Motor Disc1
CB396Vertical Support Rod1
CD1744Pole Piece1
C15103Tightening Screw1
CB393Axle with screw1
C8469Clamping Plate1
C5740Six Turn Copper Coil1
C5735Solder Trough1
SE067Solid Aluminium Ring1
C5739Split Aluminium Ring1
R7474Set of nails1
C15075Clamping Screw1
Instruction Manual1

Note: 800 Turns mains coil with a plug can be supplied separately as a substitute of demountable transformer power supply.


Demountable Transformer Kit

Safety Features:

Demountable Transformer Kit

  • Nail-melting experiment using a high current coil instead of the usual mains-voltage coil.
  • Purpose-designed power supply to safely facilitate experiments associated with the demountable transformer and accessories.
  • Output sockets provide for transformer ratio experiments and other experiments such as transformer efficiency, but voltages will not exceed 24V ac whatever combination of coils is selected. Up to 25V ac is considered safe.
  • Special 25V ac high current coils have been developed as an alternative to the potentially dangerous mains coils that have historically been provided for nail-melting experiment and others.
  • The high current coils require 25Vac and in order to prevent this higher voltage being used in transformer ratio experiments, special terminals are used to which only the high current coils can be connected.
  • Several coils are provided with a different number of windings. We have taken care to ensure that whatever combination of coils is used, the secondary voltage will not exceed 24V ac.
  • When a 25V ac high current coil is used, ‘wings’ on the coil prevent a secondary coil is mounted on the
    frame so preventing potentially dangerous high secondary voltages. But the wings don’t obstruct accessories such as the nail melting coil.

Demountable Transformer Kit