Failure Analysis on RY4S-UAC110-120V Power Relay

Gideon Analytical Laboratories received several RY4S-UAC110-120V power relays for failure analysis. A relay is an electrically operated switch. Many relays use an electromagnet to operate the switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal. Relays are used to control a high power or high voltage circuit with a low power circuit. The low power is isolated from the high power circuit. The RY4S-UAC110-120V power relays have 4PDT contact configuration, 5A contact current, quick connect relay terminals, and silver contact material. Their coil resistance is 4.29kohm. When given the RY4S-UAC110-120V power relays, we were to tasked with determining the stuck core/contact cause.

Electronic failure analysis ensued on the RY4S-UAC110-120V power relays. We had two samples to analyze. First, the covers were removed. The armature in the RY4S relay is actually a zinc plated iron core plate attached to a molded polybutylene terephthalate thermoplastic resin holding the leads for the contacts. In order for the core to close the contact, it requires a 170-gram electromagnetic field. Corrosion was visible on the contacts. We used SEM-EDS to analyze both the corroded and the non-corroded contacts. We also used SEM-EDS to scan the armature. Sample 1 had corrosion on the contacts and on the electromagnet. We used FTIR (Fourier transform infrared) to analyze that material. The FTIR scan revealed it was hydrated carboxylic acid salt. SEM-EDS analysis had revealed the corrosion, which was a crusty substance, was a chlorine by-product. The material was building up, resulting in voltage arcing over the corrosion and welding the contacts together. Sample 2 had similar problems. Once again, SEM-EDS analysis on contamination detected the presence of chlorine.

Gideon Analytical Laboratories has worked on thousands of different electrical problems. Odds are, that if a device is failing, we are going to be able to tell you why. If you are having relay problems, we are experts. Whether it is a coaxial, multi-voltage, polarized, reed, solid state, time delay, or any other type of relay, we can get the job done. If you are having problems with relays or any other electrical component, give Gideon Analytical Laboratories a call today.