Sizing motor contactors

[garbo]

The reason I prefer Danfoss for nema 4 & class 1 locations is because they offer drives that are set up to use a heat sink outside the enclosure & dissipate heat through the wall of a sealed enclosure. I don't know of other drives that offer that feature. I have also purchased drives from Danfoss that came from them already installed in the sealed enclosure. That took a certain amount of responsibility out of my hands, for a price. For different types of applications, other equipment is my first choice.

Thanks for the description of your experience.

We scrapped a Danfoss 125 HP VFD and the top of the line heat sink ran the entire maybe 30" of the drive and had to weigh at least 25#'s. The guy we gave it to was very happy with that much to take to the scrape yard.

 

[JimInPB]

At the scrap yard we switched to tesys modular starter bases and I liked them a lot. They rarely failed with how many we had and how hard we were on them and it was nice to just be able to have a bunch of them on hand and be able to use them in multiple different situations.

My experience with the modular starters, or starter shoe systems, as we called them, was consistent with yours in that they did work well and they did last. In addition, they were quick to install, and they were very quick to replace in the rare event that one did fail. Unfortunately, the industry tends to update generations of starters somewhat frequently & once that exact contactor or overload is no longer available, you then have a bigger job on your hands, especially if the cabinet has a large string of those things installed.

In other words, I think that they are great until you can't get exact replacement parts anymore. Then they become a bit of a hindrance.

 

[TwoBlocked]

"Slap a VFD on it"
is the 'oft hear cry,
When something doesn't work right
and no one knows why!

This is a process problem causing an electrical fault. Best fix is to change the flow rate, maybe a different pump impellor. But that is not always practical depending on the culture at the facility.

 

[petersonra]

Most VFDs have options to mount the heat sink on the outside of the cabinet. It is not a real popular option for various reasons. One reason is because you can't mount the cabinet that has heat sinks running out the back against a wall where such cabinets are often located.

 

[JimInPB]

Most VFDs have options to mount the heat sink on the outside of the cabinet. It is not a real popular option for various reasons. One reason is because you can't mount the cabinet that has heat sinks running out the back against a wall where such cabinets are often located.

Which brands do you normally see making that feature available?

 

[petersonra]

Which brands do you normally see making that feature available?

Ab, parker, yaskawa. I seem to recall others as well. Not every model. Ab I think only 753. Schneider has some too.