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Old 08-13-2005, 06:19 PM
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GHNorfleet GHNorfleet is offline
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Join Date: Apr 2004
Location: Woodlawn, Tennessee
Posts: 357
VFD & 3 Phase Motor vs DC Drive & DC Motor, Opinions on Each Set Up

I have been using the DC Motor Controls with the DC motors and have not had any trouble out of them so far. I have been researching the VFD Drives that will convert single phase into 3 phase and will run a 3 phase motor with variable speed. From what I have learned so far, you will have more torque with the 3 phase set up than the DC set up and I cannot comment on the VFD set up as I have not used them. I can comment on the DC set up. I use the NEMA 4 boxes which are wash down units, meaning that they can be used in harsh environments where dust and dirt etc.. abound, expecially in knife shops. These units can be washed down as they have seals around the perimeter of the DC controls and are made for these type of conditions. My research reveals that a TECO-WESTINGHOUSE FM-100 VFD Drive needs the following environment:
�� Mount the unit vertically.
�� Environment ambient temperature should be within 14oF ~ 104oF (-10oC ~ 40oC).
�� Avoid placing the Inverter close to any heating equipment.
�� Avoid dripping water and humid environments.
�� Avoid direct sunlight.
�� Avoid oil, grease and gas.
�� Avoid contact with corrosive gases and liquids.
�� Prevent foreign dusts, flocks, or metal scraps from contacting the Inverter.
�� Avoid electric magnetic interference (soldering or power machinery).
�� Avoid excessive vibration. If vibration cannot be avoided, an anti-vibration mounting
device should be installed to reduce vibration.
�� If the Inverter is installed in an enclosed control panel, please add additional cooling
using an external fan. This will allow additional airflow and cooling.
�� Placement of external fans should be directly over the top of the Inverter.
�� For proper installation of the Inverter, you must place the front side of the Inverter facing
front and the top of the Inverter in the up direction for proper heat dissipation.

This was taken from the manual which I downloaded. I am not knocking the VFD Set up, I just want to know if it would be safe in a knife shop setting where dust and metal scraps would be everywhere, or at least until the shop was cleaned up, I am very interested in using this type of set up but and waiting until I hear from some of you out there that are using this type of set up to see if it is safe or would be a problem in a knife shop.

Any and all comments are taken very serious as I am really interested in this type of set up and they also seem to be cheaper than the DC set up. I personally have not spent a lot on my DC set ups as I have found new controllers on ebay which sold for 10% of what a new unit would cost and DC motors that would normally run over $1000 for around $250 or less depending on the H. P. of the motor, but if you were to buy a good DC set up with a 2 HP motor and a matching controller, you would have to spend around the $1250 or more mark for a new set up. Any and all comments are very much appreciated!


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Gilbert H. Norfleet, Jr.
Norfleet Custom Knives
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