CATELEC CTT500GK-18 Temperature Input Module: Comprehensive Guide for PLC Industrial Automation

January 9, 2026

Historical parts record: Photos and notes below belong to this record. Confirm the offered unit’s full model, condition and available test evidence before ordering.

What is the CATELEC CTT500GK18?

The CTT500GK18 is a CATELEC power semiconductor module from Barcelona, Spain — two thyristors wired in series in one baseplate-cooled package, the 500 A / 1800 V-class build its ordering code encodes (CTT for the thyristor pair, 500 the current class, GK18 the 1800 V grade). Three stud-flag power terminals (marked AK2, K1, A) sit along the top; four gate leads — 4(K1), 5(G1), 7(K2), 6(G2) — ride the bottom tab; the label carries the circuit diagram, the C2320 lot code and the UL mark. Note on the listing title: the queue titles this article a "Temperature Input Module" — the part is a power thyristor module, and that is what this page documents. The record covers 3 modules, refurbished to as-new with a 3-month warranty as recorded. All 13 photos and 1 video below show these exact units.

3 min readContent reviewed 7 October 2026

Part details

CTT500GK18, as printed on the module label
Field	Value
Model	CATELEC CTT500GK18, lot C2320
Maker	CATELEC, Barcelona, Spain
Topology	Two thyristors in series (per the printed circuit diagram)
Current class	500 A (ordering code)
Voltage class	1800 V (GK18 suffix)
Power terminals	3 stud-flag lugs: AK2, K1, A
Gate leads	4(K1), 5(G1), 7(K2), 6(G2) on the bottom tab
Cooling	Machined aluminium baseplate, 4 corner holes + press-fit pins
Approvals	UL mark on the label
Condition	Refurbished to as-new, 3-month warranty as recorded
Quantity	3 modules
Shipping weight	2 kg total

Scroll sideways to see the full table.

Terminals and topology follow the circuit diagram moulded into the label; the class figures follow the ordering code.

Why two thyristors in series

A single 1800 V thyristor is a commodity; two of them in series double the blocking voltage, which is how this module reaches into medium-voltage territory — DC drives, electroplating rectifiers, soft starters and AC regulators running on 690 V and higher buses, where the peak of the waveform plus switching spikes demand more standoff than one die can honestly hold. The series pair shares the work through the module's internal balancing network, and each thyristor keeps its own gate: leads 5(G1) and 6(G2) fire the two halves, 4(K1) and 7(K2) return their cathode references, so the firing board drives them together. The three flag terminals along the top take ring lugs or busbar under a nut, and the machined baseplate bolts flat to the heatsink carrying the module's kilowatts of loss. Refurbished to as-new here, the CATELEC family also covers the rectifier and bridge versions of the same mechanical format — matching the exact ordering code matters because the internal circuit, not the package, is what differs. KOEED lists this module directly: the CTT500GK18 product page carries the same part.