rankrank1
Platinum Member
- Joined
- May 23, 2007
- Messages
- 749
- Location
- SW OH - near Dayton, OH
- Tractor
- 1978 Kubota L285, 1951 Farmall h, 1946 Farmall m, 1950 John Deere A, 1953 Ford NAA Golden Jubilee, 195? Ford 850, 1948 Case DC, 1948 Case SC
Excellent find James. I believe your article find answers many questions. I had not even considered that the permissible OCV limits might be different for AC and DC.
(I incorrectly always thought it was more duty cycle related with low duty cycle machines being considered "homeowner" grade and higher duty cycle machines being considered "industrial" grade. Simply assumed it was like most other appliances where the limits and exceptions were totally different for homeowner grade and industrial grade appliances).
On a side tangent: Your discovery also helps explain why welding with DC over AC can be say 16% better on some machines and possibly 36% better on some other machines. Without writing a long lengthy novel: DC is typically about 16% more efficient than AC so lets for the sake of theory consider that a constant.
Machine A: 80 OCV on both AC and DC outputs. (Welder will notice a slightly better welding performance but not earth shattering difference since it is only about 16% better assuming rest of volt/amp curve is similar).
Machine B: 80 OCV on AC and 100 OCV on DC. (Welder will notice a much more dramatic difference when welding DC over AC as they will gain the 16% percent plus the extra 20% in OCV for a much more noticeable difference between DC and AC. The volt amp curve is going to be different too).
Fascinating to me. Pretty much explains why many people notice very little difference between AC and DC and yet others will claim the difference between AC and DC is extreme.
Your one new article fact actually allowed me to learn 2 new things today. Thanks.
(I incorrectly always thought it was more duty cycle related with low duty cycle machines being considered "homeowner" grade and higher duty cycle machines being considered "industrial" grade. Simply assumed it was like most other appliances where the limits and exceptions were totally different for homeowner grade and industrial grade appliances).
On a side tangent: Your discovery also helps explain why welding with DC over AC can be say 16% better on some machines and possibly 36% better on some other machines. Without writing a long lengthy novel: DC is typically about 16% more efficient than AC so lets for the sake of theory consider that a constant.
Machine A: 80 OCV on both AC and DC outputs. (Welder will notice a slightly better welding performance but not earth shattering difference since it is only about 16% better assuming rest of volt/amp curve is similar).
Machine B: 80 OCV on AC and 100 OCV on DC. (Welder will notice a much more dramatic difference when welding DC over AC as they will gain the 16% percent plus the extra 20% in OCV for a much more noticeable difference between DC and AC. The volt amp curve is going to be different too).
Fascinating to me. Pretty much explains why many people notice very little difference between AC and DC and yet others will claim the difference between AC and DC is extreme.
Your one new article fact actually allowed me to learn 2 new things today. Thanks.
Last edited:
