Identifying a relay in an APC SURT1000XLI UPS - Page 1
Forum section: electronics / repair

author: Lorenzo_1
author_rank: Regular Contributor
timestamp: January 30, 2016, 05:19:09 am
content: I have an APC SURT1000XLI UPS that has fried one of its relays. I have had no luck identifying it or the manufacturer or finding any specs to help with a possible replacement. It's a four pin relay that appears to switch between an RHR15120 hyperfast diode and a W11NK100Z power Mosfet. It's marked 460-7200-Z and JTK 0636 (see attached image - CT4 on the board marks its location in circuit). There are no other markings on it. It is switched from a separate control board. As far as I can tell, absent any circuit diagram or service information, it appears to be the principal switching relay that activates when mains power is turned on and switched the unit from battery to 240V power operation. It was working fine for a while then, after a restart, starting switching on and off very rapidly and eventually smoked itself.If anyone has any idea what this is, where I might get a replacement, or what might be a suitable substitute I would grateful for advice.

author: electrogeek
author_rank: Contributor
timestamp: January 30, 2016, 11:41:30 pm
content: I'm not completely sure, but from the markings on the pcb, you may have a current transformer there rather then a relay

author: Senaji
author_rank: Newbie
timestamp: February 08, 2022, 02:05:32 pm
content: Compañero el componente que muestras es de un condesador doble CT4, si fuera rele indicaria RY como tambien lo indica en pla placa PCB. la CT4 (460-7200-Z JTK 1324) tambien se encuentra en el ups de 2 kva SURT2000XLI.

author: Decapitator
author_rank: Contributor
timestamp: March 07, 2022, 02:01:58 am
content: The part that you are trying to identify is a current transformer. All APC house numbered parts regardless of supplier starting with 460 are passive magnetic components.That category will include transformers, common mode chokes and inductors. The CT designation on the circuit board further identifies it as a current transformer.You should find continuity (0 ohms) between the 2 thick wires and also continuity (and a relatively low resistance) between the 2 thinner wires. It will be part of the over current protection system.The other number on the part is a date code.

author: Chris56000
author_rank: Frequent Contributor
timestamp: March 07, 2022, 02:20:20 pm
content: Hi!Current transformers don't often go defective unless the primary is physically damaged or open circuit!The difference between a voltage and a current transformer is that a voltage transformer is connected across a power supply and takes a primary current according to the load placed on its secondary (or secondaries), whereas a current transformer is connected in series between the supply and the load, and produces a given output current directly proportional to the primary current, the primary voltage being very small.Because a current transformer has a magnetic flux in its core proportional to the primary current, it is IMPERATIVE that a load is always connected across the secondary of a current transformer, otherwise a very high voltage would be developed across the secondary enough to cause breakdown if the secondary is left open–circuit, but a short· circuit across the secondary of a c.t. normally does no damage as a rule, therefore it would not normally be necessary to replace it, unless o/c as per my first sentence!Chris Williams