Picker relays too good to be true? - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: April 12, 2022, 09:30:11 pm
content: I'm looking for an economical DPDT (or 2x SPDT) relay for polarity changing of a 90VDC motor rated at 750WThe relay willNOTbe switched under loadThese almost look too good to be true: price and specificationshttps://www.digikey.ca/en/products/detail/picker-components/PC375-2C-12S4-X/12352856Anyone use them?

author: rob77
author_rank: Super Contributor
timestamp: April 12, 2022, 10:06:44 pm
content: probably you missed the 30V DC part in the datasheet..but anyways.. you need something more beefy.

author: Someone
author_rank: Super Contributor
timestamp: April 12, 2022, 10:16:58 pm
content: Quote from: rob77 on April 12, 2022, 10:06:44 pmBut when not switched under load.... that rating isnt so important. They even explicitly have a separate rating for load/no-load conditions in that datasheet!

author: rob77
author_rank: Super Contributor
timestamp: April 12, 2022, 10:22:02 pm
content: Quote from: Someone on April 12, 2022, 10:16:58 pmwhere exactly ?https://pickercomponents.com/pdf/Relays/PC375.pdfi see rating for normaly open and normaly closed contact versions.. and the double pole version is rated for 8A only which doesn't even fit the OP's requirement for 750W @ 90VDC which yields more than 8A.

author: Jester
author_rank: Frequent Contributor
timestamp: April 13, 2022, 12:37:29 am
content: Quote from: rob77 on April 12, 2022, 10:22:02 pmThat's why I stated (or 2x SPDT) in my original post. The single form C is rated for 16A, so worst case it would be at about 50% of the contact rating, that is likely conservative enough.

author: moffy
author_rank: Super Contributor
timestamp: April 13, 2022, 12:45:44 am
content: They look like truck/car relays for 24v/12v systems, at least the DC versions. Their hold off voltage will be greater than your 90v because they can cope with 240v AC. Seems reasonable, nothing special, as long as they don't have to break current at 90v DC, but you have already stated that.

author: free_electron
author_rank: Super Contributor
timestamp: April 13, 2022, 03:34:13 am
content: i would go with the 30 ampere versions.https://www.digikey.ca/en/products/detail/picker-components/PTRH-1C-15S-X/12697854https://www.digikey.ca/en/products/detail/panasonic-electric-works/JTN1AS-PA-F-DC18V/648652these are so called T90 type relays. many companies make those. there is a version with fast-on spades if you don;t want to run the high power on the board.They are used comercially in many household ovens (5000 to 7000 watt) where they work without problems for decades.Hongfa is a good chinese relay brandhttps://www.hongfa.com/HF175 could do what you seekhttps://www.hongfa.com/Product/Item/HF175Fon ebay 5 pieces for 17$ shipping included..

author: Jester
author_rank: Frequent Contributor
timestamp: April 13, 2022, 12:34:57 pm
content: Quote from: free_electron on April 13, 2022, 03:34:13 amWWCD........ I came to the same conclusion yesterday, while looking at the TE version. The faston terminals version save some cost and PCB space (less connectors). I'm going to go this direction. Thanks to everyone for their input.WWCD = Winner Winner Chicken Dinner