Question for the Electrical Guys.
Will a 10 HP 440V rotary phase converter start a 7-1/2 HP motor?
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What input voltage and phases are the convertor and what is the motor??
Here is a chart on one brand of convertor.
https://www.southern-tool.com/store/ar_10hp_phase_converter.php
Generally , you need a phase convertor almost twice the rating of the motor is the rule we used.
Post all the info and I'll look it up in my old books.0 -
I purchased a converter brand that babun gave you the link. Check their site and it will answer most of your questions. Also, their tec-support is very good - just call them. It's important to consider what device you are starting. In my case, I bought the 5HP starter for a 2 HP Bridgeport. I was concerned that it might be too small as the converter was rated at 2.5 HP max starting. I called them and was told that the 5HP was fine because of the light starting load. If I had a 2 HP compressor it would be a different story. Actually, this is all spelled out on their web site. 0 -
+440 ^^^^^^^
Starting loads are important to know.
If your motor is just going to spin up with no load applied till you do something {like engage
machinery gears}, that's different than a load sitting there waiting to move as soon as the motor turns.
I've installed many soft start systems just because of that.0 -
What Babun says...
Yes, mechanical engineers love to buy soft start units. They call them ?electronic shear pins?. When the conveyor is locked up or the fan housing is full of water, then it becomes the electricians problem.0 -
Ok thanks guys. It's a drill press, so it would be starting under no load. 0 -
babun wrote:+440 ^^^^^^^
Starting loads are important to know.
If your motor is just going to spin up with no load applied till you do something {like engage
machinery gears}, that's different than a load sitting there waiting to move as soon as the motor turns.
I've installed many soft start systems just because of that.
Though not electrical, that's similar to what people used to do on their old hot rods with high compression engines. I installed a kill switch on my big block Vette so I could hit the starter and get the motor turning before I flipped the switch which would fire the engine. Otherwise the starter had a hard time turning the engine over especially when it was hot.0 -
Smitty500mag wrote:babun wrote:+440 ^^^^^^^
Starting loads are important to know.
If your motor is just going to spin up with no load applied till you do something {like engage
machinery gears}, that's different than a load sitting there waiting to move as soon as the motor turns.
I've installed many soft start systems just because of that.
Though not electrical, that's similar to what people used to do on their old hot rods with high compression engines. I installed a kill switch on my big block Vette so I could hit the starter and get the motor turning before I flipped the switch which would fire the engine. Otherwise the starter had a hard time turning the engine over especially when it was hot.
DANG!!! you must be old too!!! I was doing that back in the early 70's!!0 -
Smitty500mag wrote:babun wrote:+440 ^^^^^^^
Starting loads are important to know.
If your motor is just going to spin up with no load applied till you do something {like engage
machinery gears}, that's different than a load sitting there waiting to move as soon as the motor turns.
I've installed many soft start systems just because of that.
Though not electrical, that's similar to what people used to do on their old hot rods with high compression engines. I installed a kill switch on my big block Vette so I could hit the starter and get the motor turning before I flipped the switch which would fire the engine. Otherwise the starter had a hard time turning the engine over especially when it was hot.
I did that also but mine was a BB 69 camaro worked like a charm
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