ProTHERMICTM PH300-TW Series Wire Preheater

PH300 Series - front view
PH300-TW - Shorting pulley view



  • For induction preheating of solid and stranded copper, copper-clad and aluminium wires up to 200°C (300°C for High Temperature (-HT) models) prior to insulation extrusion.
  • Twin wire model accepts two wires in parallel for simultaneous heating (pulleys for each wire are independently free to rotate).
  • Improve insulation-to-wire adhesion and stripping characteristics, especially at high line speeds.
  • Preheats solid wires up to 3mm in diameter and stranded wires up to 3.2mm in diameter.
  • Housed in rugged enclosures to survive harsh industrial environments.
  • Controlled using a user-friendly, menu-based LCD interface display unit.
  • Available with industry-standard communications interfaces fitted either as standard or as an option.
  • Available in different power output models suitable for all budgets and line speeds.
  • Available in 200, 400 and 480 VAC 3-phase mains supply voltage models.

Дополнительная инфо

Series Brochure
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Performance Tables >

Dimensional drawings
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ProTHERMICTM PH300-TW Series Wire Preheater

Operating principle

PH-Operating-PrincipleThe preheater is built around a large transformer and a pair of freely rotating pulleys.

The wire pair is looped around the two pulleys and through the core of the transformer. The wire entry/exit pulley is electrically conducting and thus short-circuits the wire loop to form a single secondary turn for the transformer. Electrical power delivered to the transformer primary is transformed in to a large induced current in the wire which causes rapid and concentrated heating of the wire.


The shorting pulley rim is manufactured from a special copper alloy that has high electrical conductivity and good wear resistance.

The insulating pulley is manufactured from resin bonded fabric which has good wear resistance and low thermal conductivity to minimise wire-to-pulley heat loss.

The pulleys are mounted on low friction, double row ball bearings to minimise the drag force (tension increase) on the wire as it passes through the preheater. Both pulleys are precision machined to ensure that uniform tension is applied to the wire, thus reducing SRL problems in data and telecommunications cable applications.

The preheater is powered from a 3-phase mains input, which is converted to a high-frequency supply by a specially designed inverter, the output of which is automatically adjusted to deliver the necessary power to maintain the required “Preset Temperature” regardless of wire size or production speed.

The preheater is fully protected against mains supply phase loss or brownouts.


Maximum output power / kW20
3-phase power supply voltage / VAC (rms line-to-line)400
Pulley root diameter294mm
Solid wire diameter0.53mm
Stranded wire diameter3.2mm
Stranded wire cross-sectional area8mm2
Wire preheat temperature200°C
Continuous wire tension (total on both wires)530N
Wire tension increase (at a line speed of 1500m/min)1N
Power supply frequency4765Hz
Wire line height98010001020mm
Operating temperature545°C
Ingress protection (wire entry/exit areas and pulley compartment only)IP53
Wire directionBidirectional
Wire materialCopper / Aluminium / Copper-clad / Special

Standard Interfaces

4x Logic inputsFunctionSolenoid door lock (if fitted)Emergency stop
Start preheatingStop preheating
Maximum input voltage+24V
4x Isolated relay outputsFunctionFaultState
AuxiliaryEmergency stop
Maximum contact rating50VDC / 30VAC / 0.5A
Temperature set input0 to +10V temperature control input, user scalable
Communications interfacesRS-232*
*An optional RS-232-to-USB converter cable is available for connection to USB equipped computers.


(must be specified for installation at time of manufacture; cannot be retrofitted)

Wire loop current output0 to +10 V output proportional to 0 to 2000A(rms) wire loop current
Communications interfacesPROFIBUS
Solendoid door lockLocks the access door(s) shut until motion of the pulleys has come to a complete stop.
Height plinthRaises the nominal line height to 43" (1092mm).
Twin doorsFor use in confined factory spaces where the standard single door is too large (not applicable to PH160, PH450 or PH600)