Frigidaire 5-heat Radiantube wattage & wiring

[kenmore71]

I am asking this question out of pure curiosity.
Both my mother and grandmother had 1960s Frigidaire ranges with Radiantube burner elements and the 5-position burner switches.
I know that the Radiantube elements actually had 2 separate elements in them which is why they had 3 wires leading back to the switch. Frigidaire rates the 8" element at 2050 total watts with the following breakdown: High-2050 watts, m. high-1060 watts, m. low 720 watts, low 265 watts & simmer-180 watts.
My question is: what were the wattages of each of the "elements" in each radiantube unit and what was the schematic of the 5 position switch to route 120 and 240 volts through the burner to get those outputs?

 

[tomturbomatic]

I might not be understanding your question so I will try to answer it based on what I think you are asking, but first, I don't think those were 1960s ranges. Frigidaire went to infinite controls early, before the 50s were over. Were these maybe ranges from the 50s they had in the 60s?

It is easy to determine the wattage of each of the two resistance wires by subtracting the medium high wattage from the total wattage of the element because of the way 5 heat position switches worked. One wire is 1060 watts and the other heating wire is 990 watts. We know that because both heating wires are on 220 volts on high. Medium High is only one wire on 220 volts.

 

[kenmore71]

It is possible that these ranges were from the mid-to-late 1950s. I distinctly remember the 5-position switch which was spring-loaded and did not allow you to leave the switch between settings.

As to the rest of your answer-that was what I thought initially but the math doesn't work as you drop down the list to the lower three heat settings.
See if you can follow my reasoning here:
I agree that one of the elements is likely 1060 watts. Since M High would be that element at 220 and Low (265 watts) would be that element at 110. However...
M Low is 720 watts and Simmer is 180 watts which to my mind seems to indicate that the second element is 720 watts. The problem is that 1060 + 720 = 1780. That's why I'm scratching my head.
I know that it is also possible to operate these elements in series as well as parallel which allows for two additional permutations (220 & 110). My electrical engineering math isn't quite sharp enough to reverse-engineer the answers from the data I've been given.

If I had the ACTUAL wiring schematic of one of these switches I could figure this out to my obsessive-compulsive satisfaction more easily.

 

[fltcoils]

using resistances instead of watts, P=V^2/R Given: 115V and

Element 1 = 75 ohms
Element 2= 50 ohms

simmer = element 1 @ 115V 180W
low = element 2 @ 115V 225W
med low = element 1 @ 230V 720W
med high= element 2 @ 230V 1060W
high = both @ 220V = 1780W

 

[kenmore71]

1780 watts of these elements in parallel at 230 volts does not equal Frigidaire's spec. that the element uses 2050 watts on high.

I did some further math and think I may have figured out the answer.

Frigidaire experts please let me know if this is indeed the way these systems opperate.

I now think that the two elements in a 8" 3-wire Radiantube have the following resistances: 27.17 ohms and 52.54 ohms.

The voltages I used were 118 & 236 since that is what I have seen listed in several vintage Frigidaire brochures.

When I ran the math that way things pretty much work out:

The 27 ohm element at 236 volts is approx. = to 2050 watts (High)
The 52 ohm element at 236 volts is approx. = to 1060 watts (M. High)
The two elements in series (79 ohms) at 236 volts is approx. = 720 watts (M. Low)
The 52 ohm element at 118 volts is approx. = to 265 watts (Low)
The two elemnts in series at 118 volts is approx. = to 180 watts (Simmer)

 

[kenmore71]

Now, my evil twin is wondering what would happen if you wire this thing up with both elements in parallel at 230 volts. I suspect that the results would be truly spectacular! (And not in the good sense of that word.)

 

[alr2903]

Kenmore71,  I think both elements at some increased wattage would give you the speed heat feature.  We discussed this a while back,  somehow this ZAP, was run with a timer for a few seconds or some amount of time to get the red glow quick.  I think speed heat was was to accomodate  instant coffee and  warm formula for hungry babies at 3 am.  I think its in the thread" living with a vintage frigidaire Flair". alr2903

 

 

 

 

[combo52]

SURFACE UNIT WATTAGES

The first thing to do when trying to do this type of calculation is to use the voltage listed on the appliance name plate, or the voltage in your home if you want to know the actual heat output that you will get. When the element is set on high it is running both elements in parallel @ 240 volts [ or whatever your house has ]. Frigidare like most other electric range makers used a variety of different wattage elements on different ranges and some times even on the same range. The early deep well elements were only about 1,600 watts while some 8" elements were 2,600 watts. The Friridare speed heat element was a 6" 120 volt element that the control feed 240 volts to for a variable period of up to 60 seconds causing it to be a 5000 watts for that period of time, they would turn red right before your eyes. I also find it very fascinating the different ways that manufactures designed electric surface elements. I would put electric ranges as one of the top 10 inventions for the home of the last 100 years, I would never want to have to cook on a gas range again.

 

[kenmore71]

alr2903,

Speed heat came later than the elements I am talking about and it worked differently. It was a single-element Radiantube that was designed for 118 volt operation on an infinite-heat type of switch. What made it "Speed Heat" was the Speed heat switch which threw 236 volts through this element for a short period of time when first turned on. (Somewhere I have the actual times for each heat setting). These switches were notoriously prone to failure and I have never actually seen one that was still operational. Most were replaced with a regular infinite heat switch and operated at 118 volts only at that point.

 

[kenmore71]

Frustration

When I first posted this thread I was hoping that there were some Frigidaire experts out there who actually HAD the technical information I was looking for in terms of wiring diagrams and factory specification sheets and/or field notes and who might share them with me. So far all I have gotten have been speculation and anecdotes. HELP!

 

[combo52]

SPEED HEAT

Came out in 1955 you were asking about 1960s ranges, the SH control was used on ranges where the other switches were 5 heat click types and later all infinite switches. I have the manuals that have the exact wattage's at each dial setting but as I stated they varied from year to year and model to model you have to figure which range you want know about.

 

[kenmore71]

Upon doing a little family research (pics may follow if I can find them and get them scanned from the albums) I believe the two ranges in question are as follows:

My mother had a white 30" Frigidaire from 1958 or 1959. I am pretty sure it was a lower end of the line model. I don't ever remember it having a speed heat burner and if it did it no longer worked. It did have 2 6" burners and 2 8" burners. By the late 1970s the clock and "timed bake" features no longer worked. The flourescent light also no longer worked. The oven door opened down (as opposed to the French doors that from that era had) and had no window in it. I also seem to recall that it had only one dial for the oven control.

My grandmother had a 40" in copper! I'm still searching for pics to determine a year but my best guess is 1964. It did not have a rear "well" burner and the left oven had a small storage area underneath it. Only the right oven had a window. There were 2 6" burners and 2 8" burners. I remember asking my grandmother why the left front burner said "Speed Heat" and she replied "that only worked for a few years, now it's no faster than the others." I also seem to remember that the "Heat Minder" no longer worked either. This was not an issue for her.
I also remember that it had a grounded "convenience" outlet on the far right side and that the switch for the flourescent light was on the far left.

Any info that folks might be able to share about these ranges would be great.

 

[alr2903]

Combo52,  was GM-Frigidaire the most likely of all mfr. to change their specs frequently? I know from reading imperial posts they redesigned their washer several times.  The Frigidaire design department  was so innovative.  Thanks alr2903

 

 

 

 

 

 

[3beltwesty]

In the 1950's often ranges gave the wattage for 220 volts to be conservative; not 230 or 240..

220 volts was the old standard eons ago, mostly pre ww2.

A 1950's stove would work with 240 volts that was in a modern 1950's good neighborhood; but was conservatively spec'ed for an older 220 volt neighborhood; the guy at the end of an old feeder.

Houses did not even have to have 220 volts service until about 1947. Marketing of 1950's 220 volt GE ranges often was to older pre WW2 homes that did not even have 220 volts yet. GE would help one "upgrade to 220 volts" as part of buying a 220 volt stove; ie GE sold house power boxes too.

I mention all this because on another thread somebody stated that there was never a 220 volt service in the USA. That is sort of like saying there was never dialup or dial phones.

Over time the nominal 220 volts was raised to 230 then 240 volts. It varied by region, by power company, by legal agreements. Today here at my plant the "240 volt" line is about 242 volts during the hot summers and about 246 at nights.

In California a 15 years ago I lived right by the substation at the start of the feeder. My "240 volt" voltage was about 245 to 250 volts; one blew lightbulbs all the time. I would buy super sale lightbulbs because they blew out way quicker.

In Indiana back in the mid 1960's our "240 volt" was about 225 to 235; it averaged about the old 230 volt standard.

Out 1950s Indiana house had that "todays 240 volt" at even lower; in the 225 volt range as about average..

 

[tomturbomatic]

It was not so much that Frigidaire changed specs frequently, which they did, as it was that higher end ranges usually had higher wattage elements and the offerings varied from model to model for a while. Our GE ranges had the Hi-Speed 6 inch Calrod at 1425 watts on 230, the 2250 or 2350 watt 8 inch then a lower wattage 6 and 8 inch element. On our builtin cooktop the higher wattage elements were at the front, but on our 40 inch range the 6 inch Hi-Speed Calrod was at the left rear. I have a next to the top of the line 1964 WH 30" with 2600 watt 8 inch and 1600 watt 6 inch plug out elements. Less deluxe models had wire in elements at lower wattages.

Knowing how electric surface units portion out heat as a percentage of high at 100% makes using an induction range super simple. People used to gas cooking are not used to the speed, but they also keep using induction power settings that are too high because they don't realize that medium high is 50% of high, medium usually a quarter of high, low is about half of that and warm or simmer is half of that. Another complicating factor they don't consider is the efficiency of induction compared with a gas burner.

 

[3beltwesty]

Specs and voltages

If one is "figuring wattagetoday " and you use 240 versus 220 volts you are 9.1 percent higher in voltage; and off 19 percent in wattage.

Thus a burner that is 1000 watts on 220 volts is really about 1190 watts on 240 volts

 

[kenmore71]

An interesting addition that I have gleaned from talks with my grandparents over the years was that in rural areas 220 volt electricity came with electricity period. I know that for a fact when both of my sets of grandparents (both in rural MN) got electricity in the immediate post-war period this included an electric range, an electric hot water heater and an electric water pump with pressure tank.
It was also common, apparently, for the Rural Electric Cooperative to deal in electric appliances that were sold deeply discounted (at least relative to big-city prices) to those who had recently aquired electical service. I know for a fact that my mother's parents aquired their first GE range and water heater this way in 1947. Electricity also alowed them to install a water pump with pressure tank to replace the hand pump at the kitchen sink. They had hot, running water at the kitchen sink, but still bathed in a galvanized tub and used an outhouse! Many rural kitchens went directly from wood cookstoves with a water heating attachment directly to electric ranges and water heaters.

 

[tomturbomatic]

It was the same way in the South. In the 1960s, when we did remodeling on our 1955 home, we heavied up from a 60 amp service to 150. We did not immediately get the kickback or discount on the heavyup, but we ran a wire to the kitchen while the electrician was there and when we notified the power co. that we had bought the stove, we got a credit on our next bill. The qualifying appliance had to be a range, dryer or water heater that would be a constant year-round load. They also put in an outlet for the dryer.

REA co-ops were formed to help spread the cost of running the lines through sparsely-populated regions. Electricity transformed lives. Farmers had a way of keeping their milk and eggs cool. Barns and houses had lights, not dangerous kerosene lanterns and lamps. People could read at night more easily and they could listen to the radio. They could have fans, washers, irons, mixers & refrigerators. In the Southeast, the Tennessee Valley Authority not only tamed a river system that caused annual destruction with its flooding, it brought prosperity and industry to a very poor part of the nation with a source of relatively cheap power, much the way the hydroelectric dams did in the Pacific Northwest.

 

[circlew]

Super Corox

My 1953 Westinghouse range has a "Super Corox" speed heat unit at the left front. I remember my parents having to replace it a couple times, and it had stopped working again several years before I stored the range. My mom was going to replace it with a standard burner, but never got around to it. When I work on it, I'll replace it with the regular one.
The range is a 30" model and is rated at 115/230 volts, and around 10 KW.

 

[alr2903]

Tomturbomatic, thanks for the info, I did not realize there was so many "variables" with each individual mfr.  alr2903

 

[tomturbomatic]

I have two Westinghouse ranges with the Super Corox. On the back panel there are instructions for changing it to a simple 6 inch unit by moving or removing a wire. That was done to save the control and element. My 1960 turquoise 40" Custom Imperial has both the Heat Minder and the Speed Heat units and both work but Jeff told me a method that a customer told him about how she kept her Speed Heat working for decades in her Flair range: You only start it at Warm, until you hear it click out of 240 volt operation within about 5 seconds, then turn it up to the heat you want. Since I only use it for making candy, I don't heed high settings or speed.

Both Westinghouse and Frigidaire came out with their "flasher" units while they still had 5 heat click position controls. It was the only infinite switch for their surface units back then.

 

[bryan]

radiantube frigidaire gm 1960's

I need a replacement radiantube frigidaire gm "custom imperial"
early 1960's electric stove burner.

It also says "speed heat"; it is the front left burner. The surface
element doesn't seem to have continuity. It only has two wires and
had 242v across the terminals when I turned on the switch. Don't know
its history but it definitely doesn't heat and it is getting voltage.

Can you help me? Or, point me in the right direction?

 

[norgeway]

Re Speed Heat...

Many manufacturers had these, My Norge does...and has the original switch and unit, and it still works, of course I usually start it on warm then turn it up, but if im in a hurry, it sure does work!, it has a Chromalox unit.

 

[tomturbomatic]

Good to see people cooking with electricity in Califormia

It sounds like you need a switch and the element. The Speed Heat feature consists of a 120 volt element and a special switch that pulsed 240 across the 120 unit to make it hot fast because when the voltage is doubled, the wattage is quadrupled. The process was very hard on both the unit and the switch. I think what is mostly done now since neither part is available any longer is to get a two wire 240 volt element and a 240 volt infinite switch. If you can find the Frigidaire infinite switch for a regular 6 inch surface unit, so much the better, but you can use a generic infinite switch for a 6 inch unit as long as it has the extra terminal for energizing the light that lights up when a surface unit is switched on.

What is the model # of your range? It should be on an oval metal plate over the left oven cavity when you open the door. The year will be after the RCI in the model number.

 

[combo52]

6" Frigidaire Speed Heat Element

I have good used elements for this range if you need one one, John.

 

[bryan]

1960's custom imperial stove top

The unit is a drop-in stove top on a built-in island cabinet. No oven. I think that it was similarly available as a pull-out drawer style unit. "Custom Imperial" Frigidaire/GM.

A switch that pulses 240v and then drops to 120v seems pretty advanced for 1960.

I carefully took out the surface unit assembly and could access the 2 bare wires/connectors and got no continuity with the switch off. I got 242v (!) when I turned the switch to "low."

I stopped troubleshooting at that point. I do side-jobs as a handyman and I am trying to fix the burner for one of my customers. It is unlike any other common surface element I've encountered.

The metal and fasteners located in the drip pan looked about like I expected... the part with the wires was much more shiny clean which made me wonder if the burner and switch had been replaced at some point. My customer inherited the house and that was about 7 years ago.

John, I would be very interested in your burner element. I thought that the mac.com email service was long gone.

Please advise.

 

[arbilab]

If you only have 2 wires/contacts the burner is intended for an 'infinite' or duty-cycle control. It will read mains voltage between phases, or zero. Must be best, it's what everybody eventually settled on.

They can still go wrong however. I've seen them fail to cycle and run at 'hi' setting regardless where the knob is. Bloody mess at best if you don't catch it, fire hazard at worst. Everybody breaks the rule "never leave cooking equipment unattended" and only get bit that one time in a buncha thousand.

Realizing this doesn't tell you what either Frigidaire is doing, but early GE/Hotpoint controls were:

HI--240V parallel both elements
MH--240V inner element only
M---240V series both elements
ML--120V parallel both elements
L---120V inner element only
SIM-120V series both elements

On HI both elements were equally red, but may still have been different resistances and lengths. I only have the single-coil/infinite model to look at now.

Nifty compact spaceheater below is 120V only, does the parallel/series thing for hi and lo, 1500/1200W. The 'nifty' parts are, it's barely bigger than your hand, and it's 25 years old and works like new. The company however, went out of business so you can't buy anything like it today. Note that the series is 20% below the parallel. But again, the coils are not necessarily equal resistance. They look different lengths and gauges.

 

[sudsmaster]

Fascinating discussion. I've got a Frigidaire Compact 30 with one of the large burners that only works on high. I've tried replacing it with the same results. I'm guessing there's a broken connection somewhere, maybe in the control. Not sure at the moment what year the thing is, but it seems to me the dials are not spring loaded - there are detents at the various settings but I think the other burners will operate at "infinite" levels. Been a while since I used it.

Please carry on.

 

[combo52]

6" Frigidaire Speed Heat Elements

Byran, you will get 240 volts to this element when it is first turned on, this surge of 240 volts lasts for 10-60 seconds then the control starts cycling the element @ 120 volts and never applies 240 again until the Sw is turned off and back on.

Is the old element open shorted to ground? what is the resistance you measured across the two terminals ?. Frigidaire either had a 20 amp fuse in the element circuit or a fuseable link on the back of the infinite control to protect the element from failure if the sw stayed in the 240 mode to long.

Hi Rich, your FD Compact 30 should have all infinite type switches, if it has one that has detents someone installed an older type sw.

 

[sudsmaster]

Combo,

Yes, I checked it out last night. It's an RBE-533, made about 1963 (I think). It has infinite controls. The left front burner is an 8 inch, and it has a problem heating the intermediate settings. It will go full blast on high, but will cool off on medium setting. So my conclusion is that the infinite control switch has an internal failure.

My challenge is that I can't quite figure out how to get at the controls. They are under a side stainless piece at the front of the unit. The top of the range does not seem to lift up. There are two big Philips flat heat screws under the stainless front, visible if the oven door is opened. After I shut off the circuit breaker I'll see if those allow the control panel to be lifted or removed.

The other problem is that so far I can't find a replacement for the infinite control.