You might also check with Allied Electronics, once you identify the diodes....
Allied Electronics - Electronic Components Distribution
Allied Electronics - Electronic Components Distribution
Looking for diodes for montgomery ward welder
- Thread starter Samshine
- Start date
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Another suggestion might be to check a similar welder model in the Lincoln or Miller line...see what their product manual suggests as far as part numbers or even diode characteristics. I converted my Lincoln buzzbox to DC with some massive diodes out of a welder I found at a local scrapyard...picked up the diodes for pennies...
just my 2 cents...
just my 2 cents...
I called lincoln welding today. They gave me a number that handles century welders. I called that number and told him what i had and what my welder looks like. He said he THINKS he knows what welder i have. He gave me
another number from a different place to order the part, along with a price of 59 dollars each.
When he said he THINKS he knows what welder i have. I wonder if he was THINKING right.
I really want to put the right ones back in it.
If i did buy these diodes, how can i tell if they was made for a 150 amp. welder instead of a 250 amp. welder?
Thanks everyvbody who been trying to help me.
Steve C. if you can send me the numbers i need when you can. I sure would be thankful.
samshine
another number from a different place to order the part, along with a price of 59 dollars each.
When he said he THINKS he knows what welder i have. I wonder if he was THINKING right.
I really want to put the right ones back in it.
If i did buy these diodes, how can i tell if they was made for a 150 amp. welder instead of a 250 amp. welder?
Thanks everyvbody who been trying to help me.
Steve C. if you can send me the numbers i need when you can. I sure would be thankful.
samshine
patrick_g
Elite Member
30-cycle (half wave) DC??????????
Huh? With the 60 Hz alternating current (the current previously known as 60 CPS, Cycles Per Second) there are 60 positive alternations and 60 negative alternations each second.
If you used a half wave rectifier arrangement you would get 60 (DC) pulses per second. With the full wave arrangement of the OP's welder he would get 120 pulses per second, all of the same polarity (DC.)
There is no way to start with 60Hz (Cycle or CPS) current and by using just diodes get 30 Hz DC pulses.
Patrick
Steve Bosshard
Bronze Member
- Joined
- Nov 30, 2009
- Messages
- 51
- Location
- Temple / South Mountain, Texas
- Tractor
- JD 4310 and 3 cyl 820, IH 1086 and 806
There are 60 complete cycles per second. A cycle is one complete 360 degree rotation, starting a zero, going maximum positive @ 90 degrees, back to zero at 180 degrees, maximum negative @ 270 degrees, and back to zero where it started @ 360 degrees.
Of the 60 cycles in a second there are 60 maximum positive peaks and 60 maximum negative peaks every second.
If you have only one diode in series with the secondary of a transformer (transformer for isolation from the power main) you will see 60 peaks per second because the diode only conducts in one direction. Depending on the direction the diode is wired in, the peaks may be positive or negative, but not both unless the diode shorts.
You would see the cycle start at zero, reach a maximum @ 90 degrees, return to zero @ 180 degrees, and stay there through 270 degrees on to it's return to zero, for a total of 60 half waves, hence a half wave rectifier.
A full wave configuration catches both positive and negative peaks using either 4 diodes in a bridge configuration or 2 diodes with a center tapped transformer. With a full wave rectifier you will see both the positive peak @ 90 degrees, and a positive mirror image of the negative peak @ 270 degrees for 120 peaks per second because there are 2 peaks per cycle.
My no name MIG machine uses a center tapped transformer and a full wave configuration.
Hope this helps clarify.
Best regards to all, steve
Of the 60 cycles in a second there are 60 maximum positive peaks and 60 maximum negative peaks every second.
If you have only one diode in series with the secondary of a transformer (transformer for isolation from the power main) you will see 60 peaks per second because the diode only conducts in one direction. Depending on the direction the diode is wired in, the peaks may be positive or negative, but not both unless the diode shorts.
You would see the cycle start at zero, reach a maximum @ 90 degrees, return to zero @ 180 degrees, and stay there through 270 degrees on to it's return to zero, for a total of 60 half waves, hence a half wave rectifier.
A full wave configuration catches both positive and negative peaks using either 4 diodes in a bridge configuration or 2 diodes with a center tapped transformer. With a full wave rectifier you will see both the positive peak @ 90 degrees, and a positive mirror image of the negative peak @ 270 degrees for 120 peaks per second because there are 2 peaks per cycle.
My no name MIG machine uses a center tapped transformer and a full wave configuration.
Hope this helps clarify.
Best regards to all, steve
Steve Bosshard
Bronze Member
- Joined
- Nov 30, 2009
- Messages
- 51
- Location
- Temple / South Mountain, Texas
- Tractor
- JD 4310 and 3 cyl 820, IH 1086 and 806
SRI Patrick - wish I had seen your post first - steve
patrick_g
Elite Member
No problemo amigo. Just shows great minds do think alike.
It makes me feel good every time I see there are folks out there who get it.
Oh, and no apology needed. Next time I'll probably be the one explaining what was just explained...
Patrick
Steve Bosshard
Bronze Member
- Joined
- Nov 30, 2009
- Messages
- 51
- Location
- Temple / South Mountain, Texas
- Tractor
- JD 4310 and 3 cyl 820, IH 1086 and 806
I did a little more looking. The best answer is to find the OEM part number and get a cross reference. Maybe someone somewhere has a service manual for this machine - maybe find out who made the machine for Wards and go back to them.
Next best would be to find a similar machine with a similar power transformer in terms of open circuit voltage and current capability and particularly whether there is an inductor or choke filter in the output (this can make a TREMENDOUS impact on the peak reverse voltage that the diode sees). If you can find a close match then you might sub the diodes used in that machine.
Diodes current rating assumes an infinite heat sink capability. This is not reality. As such they have to be de-rated for real life conditions.
I checked price locally for an NTE6354 - 300A, 400 PIV diode and they were in the mid $60 per each price range. I am NOT recommending this diode without much better information to go by. This is just a first glance target.
Maybe your local welding supply place may recommend a service depot or someone knowledgeable about your machine. Best regards, Steve
If you have a part number this link my help with data / cross reference info: http://www.nteinc.com/
Next best would be to find a similar machine with a similar power transformer in terms of open circuit voltage and current capability and particularly whether there is an inductor or choke filter in the output (this can make a TREMENDOUS impact on the peak reverse voltage that the diode sees). If you can find a close match then you might sub the diodes used in that machine.
Diodes current rating assumes an infinite heat sink capability. This is not reality. As such they have to be de-rated for real life conditions.
I checked price locally for an NTE6354 - 300A, 400 PIV diode and they were in the mid $60 per each price range. I am NOT recommending this diode without much better information to go by. This is just a first glance target.
Maybe your local welding supply place may recommend a service depot or someone knowledgeable about your machine. Best regards, Steve
If you have a part number this link my help with data / cross reference info: http://www.nteinc.com/
Last edited:
patrick_g
Elite Member
The diodes that came with the machine may nave been selected partly on cost by the mfg. Anyway they burned out. I'd consider replacing them with diodes with a higher current rating so they are not the weak link and burn out again. Sure, diodes with these ratings aren't cheap but having to replace them twice is more expensive and a lot more hassle than replacing them once with better diodes.
There are several reasons diodes fail, among which are:
1. too much current
2. too high reverse voltage
3. too hot
4. internal defect that may be exacerbated by any of the above.
You can buy diodes with a higher current and or PIV (Peak Inverse Voltage) rating. To fight overheating you can use a bigger-better heat sink and or add a cooling fan to blow fresh air over the heat sinks. Heat is a killer of electronics and can accelerate deterioration of solid state electronic's internal imperfections.
Welders will get abused by accident if not intentionally. Overheating of components is one of the main side effects of overworking a welder. So who uses a stop watch and note pad to stay within the duty cycle restrictions when running higher heat on a welder? Adding a fan or upgrading a fan can make a difference with any solid state electronics such as power diodes in a welder. If the unit already has a decent fan then upgrading the heat sink is a very good option.
I once was hired (during my free lance consulting phase) to make a prototype battery operated welder manufacturable. Unknowledgeable persons in the development project (after the original whiz kid left) thought they would save money and make their own heat sinks out of sheet aluminum by punching the needed holes and then bending the flanges to shape on a sheet metal brake. They thought their low cost heat sinks were working very well since the fan kept the "wings" on the heat sinks cool to the touch while the welder was putting out 180 amps. Boy were they surprised when I showed then that the solid state devices the heat sinks were supposed to be cooling would sear flesh instantly while the edges of the aluminum heat sink was cool to the touch.
It seems the heat sinks were too thin of material and had too much thermal resistance and would not conduct the heat out to the fins fast enough and so the HUGE power transistors would fry all too often. I specified a proper design for the heat sinks and had them custom extruded and (whoopee, great days in science!) no more overheating problems.
You shouldn't have to resort to custom heat sinks. Surplus stores and various sources available via the internet should have heat sinks that will tremendously improve the thermal performance over the originals and not cost much money. It would be worth it to me if it were my nice old welder and I didn't want to keep burning out expensive diodes.When I was in San Diego I could have found any number of suitable heat sinks at 2-3 different shops for a couple bucks each.
Pat
There are several reasons diodes fail, among which are:
1. too much current
2. too high reverse voltage
3. too hot
4. internal defect that may be exacerbated by any of the above.
You can buy diodes with a higher current and or PIV (Peak Inverse Voltage) rating. To fight overheating you can use a bigger-better heat sink and or add a cooling fan to blow fresh air over the heat sinks. Heat is a killer of electronics and can accelerate deterioration of solid state electronic's internal imperfections.
Welders will get abused by accident if not intentionally. Overheating of components is one of the main side effects of overworking a welder. So who uses a stop watch and note pad to stay within the duty cycle restrictions when running higher heat on a welder? Adding a fan or upgrading a fan can make a difference with any solid state electronics such as power diodes in a welder. If the unit already has a decent fan then upgrading the heat sink is a very good option.
I once was hired (during my free lance consulting phase) to make a prototype battery operated welder manufacturable. Unknowledgeable persons in the development project (after the original whiz kid left) thought they would save money and make their own heat sinks out of sheet aluminum by punching the needed holes and then bending the flanges to shape on a sheet metal brake. They thought their low cost heat sinks were working very well since the fan kept the "wings" on the heat sinks cool to the touch while the welder was putting out 180 amps. Boy were they surprised when I showed then that the solid state devices the heat sinks were supposed to be cooling would sear flesh instantly while the edges of the aluminum heat sink was cool to the touch.
It seems the heat sinks were too thin of material and had too much thermal resistance and would not conduct the heat out to the fins fast enough and so the HUGE power transistors would fry all too often. I specified a proper design for the heat sinks and had them custom extruded and (whoopee, great days in science!) no more overheating problems.
You shouldn't have to resort to custom heat sinks. Surplus stores and various sources available via the internet should have heat sinks that will tremendously improve the thermal performance over the originals and not cost much money. It would be worth it to me if it were my nice old welder and I didn't want to keep burning out expensive diodes.When I was in San Diego I could have found any number of suitable heat sinks at 2-3 different shops for a couple bucks each.
Pat
Thanks everyone for your input.
I called centrury and they gave me a part number on the diodes 214 004 666
Has anybody have a ref. book to see what size diodes this is?
I have four diodes in my welder. The sales rep. told me all four have the same part number.
If i upsize, how big can i upsize? and
Do i need to upsize all four diodes?
Again thanks everyone for your input.
All info. will be thankful.
samshine
I called centrury and they gave me a part number on the diodes 214 004 666
Has anybody have a ref. book to see what size diodes this is?
I have four diodes in my welder. The sales rep. told me all four have the same part number.
If i upsize, how big can i upsize? and
Do i need to upsize all four diodes?
Again thanks everyone for your input.
All info. will be thankful.
samshine