Re: ballast resistor getting hot
[Re: frank]
#2277455
03/28/17 12:21 AM
03/28/17 12:21 AM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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It'll get hot enough to burn your finger after awhile.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: ballast resistor getting hot
[Re: L.R Helbling]
#2278824
03/30/17 12:32 PM
03/30/17 12:32 PM
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Joined: May 2003
Posts: 6,566 Downtown Roebuck Ont
Twostick
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Downtown Roebuck Ont
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Perfectly normal. It functions as a heat sink for your ignition circuit. Without it, the same thermal energy would be transferred to your ECU, coil or wires cooking them in their own juices. First time I've ever seen a resistor described as a radiator... It's not by the way. Resistance in an electrical circuit generates heat and depending on the components, light too. If it says Lucas on it smoke is a given... Kevin
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Re: ballast resistor getting hot
[Re: Twostick]
#2278873
03/30/17 01:57 PM
03/30/17 01:57 PM
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Joined: Dec 2016
Posts: 381 Ottawa, Ontario
L.R Helbling
enthusiast
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Perfectly normal. It functions as a heat sink for your ignition circuit. Without it, the same thermal energy would be transferred to your ECU, coil or wires cooking them in their own juices. First time I've ever seen a resistor described as a radiator... It's not by the way. Resistance in an electrical circuit generates heat and depending on the components, light too. If it says Lucas on it smoke is a given... Kevin Never said it was a radiator. A heat sink is an electrical component. The ballast is a resister that captures heat. The resister in the ballast is encapsulated by ceramic. This material can take a lot of heat and the location of it allows it to release that heat without affecting any of the other nearby electrical components.
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Re: ballast resistor getting hot
[Re: L.R Helbling]
#2278891
03/30/17 02:14 PM
03/30/17 02:14 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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Perfectly normal. It functions as a heat sink for your ignition circuit. Without it, the same thermal energy would be transferred to your ECU, coil or wires cooking them in their own juices. First time I've ever seen a resistor described as a radiator... It's not by the way. Resistance in an electrical circuit generates heat and depending on the components, light too. If it says Lucas on it smoke is a given... Kevin Never said it was a radiator. A heat sink is an electrical component. The ballast is a resister that captures heat. The resister in the ballast is encapsulated by ceramic. This material can take a lot of heat and the location of it allows it to release that heat without affecting any of the other nearby electrical components. That's so bad, it's not even wrong. A heat sink is a radiator, it takes heat from an electrical component, like a power transistor, and radiates it out into the environment. A ballast resistor is nothing more than an resistor that can tolerate high heat generated during it's use, as a resistor not as anything that "captures heat". A ballast resistor is NOT a heat sink. The fins on the ECU would be a heat sink, one that radiates the heat from the power transistor in the ECU. Look up wire wound ceramic resistor, which is what a ballast resistor is.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: ballast resistor getting hot
[Re: frank]
#2278908
03/30/17 02:46 PM
03/30/17 02:46 PM
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Joined: Dec 2007
Posts: 18,157 Mass
DAYCLONA
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I Live Here
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Mass
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Installed new in tank electric fuel pump. When running wires in engine bay (I was looking for a keyed power wire for relay) I noticed my ballast resister was getting very warm; almost too hot to touch. Is this normal? Key was in "on" position for less than 10 minutes, probably about 5 but less than 10. 6.4 volts in and 10.5 volts out if that makes any difference. If the heat is of some concern for you, there are several other factory/aftermarket ballast resistors with different OHM values, determine what you have first, and what your ignition system requires,... I had the same concerns on various builds when the ballast was a little too hot and raised some concerns
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Re: ballast resistor getting hot
[Re: DAYCLONA]
#2278919
03/30/17 02:59 PM
03/30/17 02:59 PM
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Joined: Jan 2003
Posts: 15,434 Omaha Ne
TJP
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Omaha Ne
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Re: ballast resistor getting hot
[Re: L.R Helbling]
#2278950
03/30/17 03:48 PM
03/30/17 03:48 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
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http://www.atomic4.com/faqres.htmMost definitely it's a heat sink. In order to read about how a resistor set in ceramic can function as a heat sink, I offer the link above to better inform you on what the resistor does in a primary ignition circuit. That is what the ceramic is all about and that is exactly what it's function is. Your link does not even support your statements. I don't know where you get this from, but I can state definitely, you are wrong. Wire wound ceramic resistors are for high heat applications. They may or may not include a heat sink in the design, but the ballast resistor does not include one and the heat sink is not part of the resistance in applications that use one, which I will once again state does not include the ballast resistor.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: ballast resistor getting hot
[Re: frank]
#2279350
03/31/17 04:01 AM
03/31/17 04:01 AM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
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Balt. Md
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The reason for the ballast was to drop the voltage and amps in the ign primary circuit so the points wont burn up to soon and to limit the current flow through the coil so it last as long as it should. Mopar still uses the ballast when they went to electronic ign but not all manufactors did as some built the coils to work with a full time 12 volt feed and they can also limit the current flow by the electronics controlling the dwell. But the ballast is a resistance put in the primary ign circuit before the main load (the coil) in the circuit. It gets hot because of the electrical resistance it puts in the circuit to limit voltage and the current flow. Its not made to be a heat sink but they put it in the ceramic because they know it will get hot enough to maybe burn someone touching it when its in use. Its just like having a loose connection in an electrical circuit that can get hot because the loose connections puts more resistance in a circuit. Think of it like a crankshaft not getting enough oil to the journals. They heat up and get hot because the resistance to turn is much more with less oil and that resistance will build heat. Look at a blower motor resister as it puts resistance in the circuit before the load (blower motor) and it can get red hot on the lower speeds when it puts the most resistance in the circuit. I am sure the engineers dont want it to get red hot but it does heat up because of the electrical resistance it puts in the circuit. It only makes sense because the only reason for the ballast in the ign circuit it to limit the current flow and drop the voltage. They dont need it to get hot but thats what it does because of how much resistance it puts in the circuit. The only reason some may have ceramic on them with fins is to help disapate the heat which is why many blower motor resisters are in the housing so it blows air over the blower resister to help it disapate some of the heat. Ron
Last edited by 383man; 03/31/17 04:03 AM.
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Re: ballast resistor getting hot
[Re: frank]
#2279432
03/31/17 10:56 AM
03/31/17 10:56 AM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
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Phila. Pa.
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Function of Ballast Resistor with Points Ignition. Essentially as described above (protect points) and uses temperature to increase flow at higher rpms to offset reduced dwell time. Attachment. 1969 Dodge Service Manual, page 8-46: Function of Dual Ballast Resistor with Magnetic Pickup Ignition. Chrysler Master Technicians Conference, "Ignition System for 1972," page 5 FWIW, the Ford Duraspark systems I've worked with on AMC Jeeps used a resistance wire to the coil instead of ballast resistor. The wires are quite long, doubled back on themselves whe needed to keep it within the harness loom. Using a wire presumably spreads the heat created over a larger distance, and sufficiently so it doesn't degrade the carrying capacity of the otehr harness wires. In any event, if an electric pump is drawing power through the resistor either in Start or Run, this will be a problem.
Ballast Resistor function. 1969 Dodge Service Manual.
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