newbee question on ATLAS remote switches

[Anonymous]

lets see if i'm getting this right, then......

Atlas switch motors - Peco too, apparently - consist of an armature sandwiched between two solenoids. In order to "throw" the switch, one zaps the relevant solenoid with a jolt of electricity and it pulls the armature towards it, thus throwing the switch as required. This electrical jolt originates from a "CDU" which recharges itself ready for the next punch. Correct?

ok..... I'm new to this hobby, but I associate the term "CDU" with car ignition systems. In fact Capacitor Discharge Units are nasty beasts. The output from these units take the form of an instantaneous high energy pulse which quickly tapers to nothing. Has anyone ever asked a switch motor its opinion about being given such treatment?

If I'm correct here, most of the energy would be lost on the onset of current flow within the motor coil. Since coil resistance is very low without current flow, most of the energy available would be "lost" in building up the initial magnetic field, with little left over to maintain the field and provide the pull for the motor to function.

One way round this is to provide a large enough energy store to have a long-enough pulse to be effective. The downside of this is that the larger the energy store, the bigger the initial surge would be, and this, in my opinion, is detrimental to the motor coils.

Instead of providing an uncontrolled high energy spike, wouldn't a realtively low powered controlled constant pulse do the same thing and shift the motor without the jolt? If so, then I'd say that the motor would last longer.

Such a pulse can easily be generated simply by pushing a switch and temporarily connecting the coils to a supply.

So I'd say thra***he CDU's and bring on the simple switch!!!!

Feel free to lynch me dudes!!!!!!!!![:-^]

[NZRMac]

Unfortunately if one holds one's finger on the simple switch it burns out one's turnout motor, that's why CDU's are used. I've got one and have never had a problem.

A low powered controlled pulse sounds like more electronics than the CDU?
.[2c]


Ken

[Don Gibson]

THE CAPACIVE DISCHARGE UNIT store's up enough energy to 'kick' more than one HO selenoid at a time - how many - depend's on the size of the capacitor.
This enenergy is insufficient to heat the coils due to it's short duration, and once expended takes time to rebuild - usually several second's.

Since most manufactured HO Twin Coil switch macine's take 3 instantaneous peak amps to move their slug and do any work, and few of today's power pak's have that capacity, the CDU is an acceptable solution when one want's to throw 2 or more switches simultaneously. It is also nearly impossible to burn out or overheat the winding's, which a new person can with semi-momentaries and and their major complaint.

MOTOR DRIVEN switch machine's sell for $15-$20 - double the price of twin coils. Guess what 'beginer's' prefer to buy?

[Anonymous]

hmmmmmmm...............like I said, I'm a rail newbie, and am still bedding in, but you have a valid point - so is there an empirical formula on current demand based on the number of points activated together?

I am interested in controlling up to 8 ATLAS motors with the minimum of switchery. Diode matrices are one way, I guess. My take on the method is to have a change-over switch for each motor. The route would be kinda programmed in by throwing the switches and then activate the lot by square pulse of known length. - monostable thingy.
This way ALL motors would recieve a pulse, but this means that the power supplied to them is always constant.

I have done some experiments in this direction and found that motors change over from as low as 5V. Also, I found out that they tend to heat up rather quickly - thus validating Don's point on blown motors.

Any kind thoughts on the above, people, please?[bow]