I am having trouble with a starter.
It's a small Telemechanique Tesys U-line with Advanced Control Unit; 12 Amp 460V. It serves a primary chilled water pump so it stays on for hours at a time. The motor is rated 4.2A and actual draw is 3.00, 3.04, 3.12.
The pump and starter are three years old. When they were commissioned I set the starter at 3.8A and had a nuisance trippage within a day or two. I raised the trip point to 4.2 and the only times it has tripped since then there were known power events, thunderstorms, etc.
Recently it has tripped without any obvious power events having occurred. When I checked line voltage it was 489, 489, 491; voltage drop across L1-T1, L2-T2, and L3-T3 were all 0.00V. The starter is in a panel with two drives and a couple of other starters. Per infrared thermometer this starter is not getting hotter than other components. But the panel is getting fairly warm. The day of measurement the mechanical room got up to 100F and the panel got up to 120F, it rained a little in the afternoon so the room didn't get very warm. There's a west wall with sun exposure and I intend to check panel temp late in the day but the past two days there's been cloud cover.
The starter hasn't tripped since I raised the trip point to 4.6A.
I don't want to replace the starter just for grins, though I have approval.
What effect does ambient have on trip point?
The catalog data says it's ambient compensated and rated up to 158F, but the trip curve says data is for 70F ambient. If ambient has no effect on trip point, why doesn't it say "trip curve is for -10F to 158F" or the like?