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HM 2000 Gets Warm ?


Guest Chrissaf

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Last month purchased a HM 2000, it keeps getting quite warm and green lights keep  going dim, is this anything to worry about 

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Anything that consumes power is going to get warm.

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In order to give more accurate targeted advice. One would need to know what locos you are controlling with the HM2000 and whether it gets warm when controlling two locos at once. Older locomotive motors consume more power than more modern rolling stock. Also the speed you operate the locos at will have a bearing on the amount of current (power) they consume. Thus the controller is more likely to get warmer if you are running two older locos at brisk speed than one loco at a snails pace.

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If the green LED is on the output of the HM 2000 (I believe it is?) then its brightness will be affected by the output speed control knob position. Low speed dim, high speed bright etc.

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The HM 2000 is an old design and has a multiple winding transformer at its core. This means that power control has to use 'linear' technology as opposed to 'switch mode' technology. In simplistic terms this older 'linear' technology generates more heat as part of the process of controlling power delivery to the track. Most of the heat generated [but not all] will be radiating from the transformer.

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TIP: As a newbie poster on the forum, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

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See also – further TIPs on how to get the best user experience from this forum.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

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I have a H & M 2000 & Chris is right about well every thing he has said above - but just wanted to say the bit about...

 

If the green LED is on the output of the HM 2000 (I believe it is?) then its brightness will be affected by the output speed control knob position. Low speed dim, high speed bright etc.

Yes that is right!!!

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There have been seceral models of the HM2000 controller, the early ones having a transformer as described by Chris and the more recent ones being electronic. The early ones will definitely get warm. The later ones I have no hands on experience of.

 

In either case the red led is a power indicator on the ‘input’ side of the circuits and the two green leds are on the ’power to track’ side of the circuits, so again as Chris said and as confirmed by JJ they will brighten with increasing throttle.

 

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jimbo, if they are plugged in, they get warm. I foolishly left my  DC layout on, overnight. I have 15, H&M various controllers. Fortunately, all was well, but you could have fried an egg on them. Kinda warm. Everything needs to be turned off. I have now fitted leds to both DC and DCC, layouts, so that i am sure, they are off.

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As a very crude analogy - picture your HM as a garden hose, and the electricity as water.

You have plugged in the hose to the water pipe (mains wire) and turned the tap on (the switch on the socket) so the hose fills with pressure. Because you haven't pressed the spray trigger (speed controller) the water can't spray onto the garden (the railway), but the pressure is still there.

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Now it's a transformer/controller we are looking at - so the electrical pressure (called Amperes) is still there, even though the speed controller is set to zero. The transformer is still working to apply the pressure, converting the 240 volts to 12 volts. It just can't go anywhere.

To take the pressure off, you have to switch the power off (turn the water tap off).

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240 VAC mains transformers vibrate at 50 cycles per second ... that's what they do ... that is the humming you can hear. Anything that vibrates generates heat. A basic law of physics.

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A transformer has a primary winding and secondary windings. The primary winding is still a complete electrical circuit and will still be drawing some current, even if the secondary winding is idle. Granted not as much current compared to when the secondary winding is delivering a current flow, but some current all the same.

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Just the fact that there is a live 50 cycles per second AC power connection to the transformer primary will still produce some vibration and thus heat.

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Thus 'best engineering practice' is to completely disconnect the mains input on any transformer powered device when not in use.

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Before someone brings up the comment about mains powered devices that have 'standby' power options such as TVs PCs and the like etc. These devices tend to have 'switch mode' power supplies rather than 'linear' power supplies using transformers. Thus their power operating methodology is completely different.

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Mr Pedant butts in...

 

In the water analogy:

Pressure = volts

The more volts the higher the pressure.

 

Flow = amps

The more amps passing the greater the flow.

 

Spray trigger amount = ohms

The more open (least resistance) the greater the flow, the less open (greater resistance) the less the flow..

 

/media/tinymce_upload/2128c8fd5c9c6beaff8674afbbf5614b.JPG

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