Vfd

[archerybs]

I bought a 5hp Bosch Rotary Claw pump from ebay this summer. I need to get a phase converter/VFD for it since I only have single phase available. Has anyone built their own or does everyone just buy them set up?

[Amber Gold]

The VFD is the phase converter. I bought mine from driveswarehouse.com. Reasonable to deal with except for warranty claims. I had a VFD fail 2 weeks into it's service, and they told me Hitachi said it was a non-warranty failure. I bought the same thing again and no issues with it after three seasons.

Find someone to help you program it. I have heard from others that driveswarehouse is good in this regard. They'll walk you through the setup.

[maplecrest]

last year had same problem as josh. bought unit same place. my problem was i did not let warm up when i put power to it before trying pump. fried it. ordered same one ,guy in beach chair sucking on favorite beer walked me thru set up.warning when cold let unit run 15 minutes or so before trying vac pump

[Amber Gold]

Interesting, they never told me that. When mine failed, it was mid-day and it'd been running for a while. I was in the SH when it happened, and it just shut off, and wouldn't start up.

The nice thing with VFD's is you can set them up so they protect the pump motor for undervoltage, overvoltage, and other things, and you can set it up so it restarts if it trips from one of the settings. Pretty handy if something happens when you're not around.

[Three Maples]

VFD's are nice but you can do the same job with a oldler three phase motor. It is call an idler I run my machine shop on an idler. The three phase motor will not start on sigle phase 220 wihout some tricks, but once started it will provide an "atrifical " third phase. The idler has to be 1.5 times larger that the load so if you have a 2 hp motor you need a three hp idler. The idler can be started one of two ways using start capacitors that phase shift the artifical leg during start or by spining up the idler with a small single phase motor or I have used a starter rope on the shaft. Static phase converters are availabe online but you loose power. you only get about 3/5 the power of the motor rating. I have designed an auto start for three phase idlers but all you realy need is to use the spin up method. I do have the scematic if you are interested. As a disclaimer some modern three phase motors do not like the artifical phase and if you are useing a magnetic starter you need to be very careful about the wiring or the starter will not pull in and could smoke.
Some VFD's are designed to have single phase in and 3 phase out. You can use a 3 phase Variable Frequency Drive that is 3 in and 3 out if you get it big enough so that the the two legs in can hanlde the load. VFD's are designed to control speed in a 3 phse motor and are a bit of overkill to use as a convertor.