Power Converter Hum?

[Road_Trip_Rob]

Hello,
I have a project camper that I am working on to get it on the road.
It's a 1997 Dutchman. It has a Magnetek 45amp power converter with battery charger. Model# 6345. Everything works fine such as the AC, fridge, water heater and lights but I have noticed the converter has a Hum when it is plugged in even if everything is turned off. I took the front cover off the converter and the hum seems to be coming from a transformer. Is this normal? It's not real real loud but I think it will bug me when trying to sleep. I also notice a small fan in the converter that was not running. It spins freely but does not come on. The hum is not coming from this fan.
Thank you for any help on this, Rob

[edatlanta]

Why do transformers Hum? They don't know the words.

[BFL13]

The MH in sig had a 6345. I removed the "lower portion" (the converter), jumpered the fuse panel so it was not "split" (the 6300 converters have a red and a blue pos wire where newer converters have just the one pos wire that does all the fuses.

You would need a new fuse panel unless you jumpered the red and blue on the old one. I then put in a straight deck mount converter handy to the battery bank (I chose a PowerMax)

You don't have to get a new replacement "lower portion", but you can. A deck mount will fit there or go to a better location nearer to the batteries. As mentioned above by others, PD makes replacement lower portions and so does PowerMax and even WFCO, but don't get a WFCO! (the Ultra kit--frying pan into the fire deal) and don't get a 7300 either.

You can get any "three-stage" brand deck mount 45 amper and it will be good enough.

[MEXICOWANDERER]

Another asset very much positive for vendors of fluorescent tubes for the old Thin Lite ceiling fixture is the incredible speed at which the Magnahum turned 8 watt and 15 watt tube ends black and heated them blistering hot.

[wa8yxm]

That converter has not been made since before the turn of the century and you really should upgrade to something more progressive. More on this later. Including the explanation of the pun in that statement.

YES. That big Ferroresonant transformer is made up of coils of wire wound around a core made up of hundreds of iron leaves. each leaf is coated with varnish that both sticks them together and holds them in place.. Over many years the varnish dries and flakes away allowing the leaves to vibrate causing the HUM you hear.

THis is normal. and does not indicate impending doom.

BUT the unit has very poor voltage regulation It is actually two devices in one case bolted to more stuff (We will get to that later) A very slow battery charger And a 2nd 12 volt UNFILTERED power supply and a relay that links them in the absence of shore power.

The Battery side is (in theory) filtered (By the battery) DC for things like a Radio. But the charger can not even keep up with most radios.

The other side runs lights. Water pump Furnace and the like.

Now.. The charger being unregulated is well known for boiling batteries dry by overcharging.. This is why you really should upgrade

THe "More stuff" is the breaker and fuse panels.. YES you can remove the "Electroncis" from behind the panel.

Now.. Progressive Dyanmics (Recall I mentioned a pun.. Progressive) makes a model 4600 series. This is the electronics in a plain steel wrapper (optional) which replaces the "Guts" of the Magnetek .. and other .. Converters

A top of the line 3-stage+ converter which treats your batteries very very nice

To replace the 6345's electronics you get teh SMALLEST 4600 You need to add one jumper and job done.

[DrewE]

As others have said, the hum is a standard feature of many of these old converters.

One benefit is that you can locate where the RV builder hid the converter when it's a deck mount unit that's not part of the electrical distribution panel.

[MEXICOWANDERER]

Do-It-Yourselfer's can install rubber bushings in the transformer mounting and eliminate 95% of the hum. I did that with my huge Sola ferroresonant "Line Tamer" AC voltage regulator. Only problem is the gray beard Magnahum isn't worth ten cents.

[SidecarFlip]

If I were you, I'd lose the Magnatek toaster pronto. I almost burned my RV up with one. The transformer not only hums, it gets hot. Mine got hot enough to scorch the flooring below it. I put in a PD and never looked back.

[Bobbo]

The Progressive Dynamics PD4645V is a direct drop in replacement. Remove a few screws, take off two power wires hooking it to 120v AC and two (or three) power wires hooking it to batteries and house 12v circuits, then slide in the replacement and re-hook wires. I did it in my previous Class C, and in my new TT.

You can even upgrade to their 55 amp model for an additional $10.

[Road_Trip_Rob]

You guys are the BEST!
So glad I joined this forum!
Thank you,
Rob

[ksg5000]

The noise is pretty std for old Magneteks. Many people tend to upgrade to smart converts which are quiet and change their power output depending on the state of your battery. I replaced my Magnetek with Progressive Dynamics 9245 - lots of online videos on how to swap out converters.

[Matt_Colie]

Rob,

The old Magneteks were a Ferro-Resonant design that used line frequency to maintain a stable output voltage. They are always noisy. They are also not very good as a converter charger. The manufacturer had to pick either a good output voltage to charge batteries fast (that will damage batteries with time, or a safe storage voltage (that will take forever to recover a depleted bank).

The newer multi-stage (aka smart) units do it all much better and quietly. If you have a good house bank or plan to install one, this is a good mod to make.

Matt

[YC_1]

You are correct about the transformer. The fan most likely comes on when it gets to a specific temp.

If the noise will bother you buy a new one but do get a more modern one with better specs and features.