Simple Question about Thermal Cutoff (tco) & Fuses

"j barnes"

** Yes.

The amp rating is not important long as it is more than 4.

.... Phil

JB-

I can't imagine the tea kettle cost much over $30, so it is not cost effective to buy the exact part. The price appears to be calculated to encourage you to buy a new samovar instead of repairing yours.

From where did you obtain the specifications for the original part? What are the samovar's electrical ratings for voltage and power? They may be on the bottom or next to the electrical wire.

Several coffee makers I checked all use power in the 600 to 800 watt range. If the samovar operates close to 480 watts (4 Amperes at 120 Volts), you would not want the fuse to blow at 4 Amperes. I suspect the function of the original part was to protect against a fire when the pot was operated after all the liquid had boiled away. So the 4 Ampere rating is a maximum operating current, not necessarily the current at which it blows.

How were you going to install the replacement? Soldering is not a good idea. Solder could melt under normal operating conditions, and soldering might damage the TCO if you aren't careful. Crimping is the better approach, but it is difficult to get a good crimp with solid wires. Some TCOs come with a "crimping ferrule". It is a small metal tube (brass?) that you insert two wires into and crimp them together.

Fred

"Fred McKenzie"

** The 4 amp rating is mostly to do with the tripping temperature - up to 4 amps of current can pass without changing the tripping temp by more than a few degrees due to self heating.

IOW, at 4 amps there is only a few degrees C rise in the temp of the device.

Similarly for the 10 amp types.

.... Phil

that runs immediately after the 120v input plug =A0The TCO is rated at 4am= p and 152C. =A0I cannot locate this fuse anywhere but here:

ply add a 4amp fuse immediately before or after the TCO? =A0Intuitively thi= s seems like it would work, =A0more than 152C the TCO burns, more than 4amp= s the other fuse blows.

A 22QBP152 is the same part and retails for about $7

FWIW, I have delved into several of my wife's sewing appliances that were originally designed for European countries and they seem to forget the current issue in adapting from 240V to 120V for the NA market. Her two irons both failed from the overtemperature safety cutout [self resetting thermal breaker] contacts burning, even through the cutout should never have tripped. They were rated for 6A and the irons draw about 12A at 120V. In both cases the cutout is spot welded to the base assembly and not replaceable. New plate $85. Similar with the old foot controllers for sewing machines where the contacts look to have ample voltage clearances, but marginal contact area. One Bernina has actually burnt one contact half away over the last 50 odd years. I cannot see a Samovar taking much less than 1000-1200watts, like most kettles, so I would, myself, use a 10A rated cutout. Naturally, when installing it, it is best to crimp the connections or spot weld but, in any case, you must wrap the new one time thermal fuse in a wet rag to keep it cool while attaching it.

Neil S.

"nesesu" "Phil Allison"

FWIW, I have delved into several of my wife's sewing appliances that were originally designed for European countries and they seem to forget the current issue in adapting from 240V to 120V for the NA market. Her two irons both failed from the overtemperature safety cutout [self resetting thermal breaker] contacts burning, even through the cutout should never have tripped.

** The device in question here is a "one shot" thermal fuse.

There are no contacts inside.

I cannot see a Samovar taking much less than 1000-1200watts, like most kettles, so I would, myself, use a 10A rated cutout. Naturally, when installing it, it is best to crimp the connections or spot weld but, in any case, you must wrap the new one time thermal fuse in a wet rag to keep it cool while attaching it.

** Hardly necessary if you crimp the wires - and anyone with reasonable soldering skills can solder the lead ends quickly without heating the body to 152C.

..... Phil

Fred McKenzie wrote in news: snipped-for-privacy@5ad64b5e.bb.sky.com:

I have a Presto Fry Granddaddy deep fryer that the TCO blew when the bimetal thermostat contacts welded together. AFAIK,they don't make the Grandaddy anymore,so I unstuck and filed the contacts,then bought a new TCO at Radio Shack !! that was a few deg C lower than the original,but same current rating.It's been working fine ever since. I bought new crimp ferrules at Skycraft Surplus.(local store,Orlando,FL.!)

--
Jim Yanik
jyanik
at
localnet
dot com

d64b5e.bb.sky.com:

y

tal

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Thank you everyone for all the helpful advice and suggestions! I'm glad everyone reminded me to crimp rather than solder. I can be a real space case when I get caught up in repairs so it was a great reminder.

For the curious, the $30 part is for a $170+ Samovar so I don't think they are trying to force a new sale. It is hoity-toity expensive German made samovar used for shi-shi-fu-fu parties. Looking at the thing, I would have never guessed somebody would pay so much for it. I'm certain it cost a fraction of what it sold for to make it and there were dozens of happy people along the chain of sale between Germany and here who tacked on a nice healthy profit for themselves.

Personally, I'm the kind of dude who would bust out with my trusty decades old plastic coffee-stained Mr. Coffee or my newer Proctor Silex tea kettle if I need quick boiling water, if my friends don't respect me because of that they aren't my friends. However, this is the female species I am dealing with here. Such uncouthness as mine displayed by the hostess who is requesting the repair would bring many years of shame and embarrassment on her family for generations to come.

Of course I'm just kidding about the shame and embarrassment lasting for generations, but this repair is bound up in culture and psuedo- sophistication rather than pure utility.

Thanks again!