Old stuff needed

Putting together classes to train future electric vehicle service and repair techs. Will include DC motor control.

Want to put together a demonstration board to show shunt series and compound motor operation and control. Have 100 0 100 amp ammeter and tach 600 0 600, main line contactor and main line knife switch and fuse assembly. I want to use to demonstrate CEMF, reversing and dynamic braking.

I want all to be plainly visible to students at a 15 foot distance. Intend to use knife switches so students know and can see a switch position.

IF students are to operate this then I will more than likely keep voltage at 48 or less. Yes I realize there can be high currents - there will be an instructor held E stop "chicken switch" provision for safety.

WHAT I NEED are double pole double throw knife switches say 50 amp capacity (or more).

Anybody have some of this old stuff in their neat "stuff" piles?

Free would be nice - but there are those practicalities,,, Will pay shipping of course.

Also looking for inspiration and better ideas and views.

Dan Bentler

I can't help you with any old hardware Dan (5S is the corporate religion) but I can offer a suggestion for consideration.

I think I learned more about DC motors in my early years from variac controlled motors because the system is so easy to visualize and understand. You will want to quickly move on to modern DC drives because that is what today's techs need to know, but for early visualization and understanding the basic principles without any smoke and mirrors a variac and rectifier might be worth considering. (Besides, they might just encounter those in the field too.)

TConnolly said:

I can't help you with any old hardware Dan (5S is the corporate religion) but I can offer a suggestion for consideration.

I think I learned more about DC motors in my early years from variac controlled motors because the system is so easy to visualize and understand. You will want to quickly move on to modern DC drives because that is what today's techs need to know, but for early visualization and understanding the basic principles without any smoke and mirrors a variac and rectifier might be worth considering. (Besides, they might just encounter those in the field too.)

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How is a good pack rat scrounge artist to get by with this 5S stuff?

Forgot to mention I would use a variac in many cases but if I can scrounge up enough stuff would sart them off with resistive starter.

May also do with batteries and keep seriesing up for higher voltage.

MORE inspiration needed.
Dan

Found knife switches and other real old DC stuff right here in Seattle. Good prices. If anyone needs antiques let me know. They are intending to clean out this section and scrap it all out.

Stuff is becoming like hens teeth.

Dan Bentler

If you really want to have some fun and expose your students to some really clever very early 20th century engineering see if you can dig up an old mercury vapor rectifier.

TConnolly said:

If you really want to have some fun and expose your students to some really clever very early 20th century engineering see if you can dig up an old mercury vapor rectifier.

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We still gain our DC supply from 1000kW & 750kW Mercury Arc Rectifiers!!

We are having the same problems at the minute with regards to apprentices, do you teach them the 1950's technology that still runs part of the plant or do you dive straight in with the modern gear.....

More than likely I will not teach the resistor bank starting for DC motors. However if that is what customer wants I have knife switches and resistors. This is stuff I learned the trade on. 3 step resistor to start 400 HP 250 VDC motors on submarine.

Will use variac and rectifier for power supply. Small 1 HP or less motors - I am the one who has to carry this stuff to class room. Most classrooms have 120 VAC and only 1500 Watt at that so gotta keep it small.

Will use the above to lead into the solid state DC controls and VFDs. It still boils down to basic motor control.
Never been to England - am willing to go.
Dan Bentler

nic00 said:

We still gain our DC supply from 1000kW & 750kW Mercury Arc Rectifiers!!

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Somehow I always suspected that you Brits just hadn't quite yet moved on from Stonehenge.

Dan do you need any old DC drives? I might have some in the "it's not that big " pile.

Jeff

I am not certain at this moment. If less than let us say 10 HP and less than 25 lbs then I may be interested in next six months. Am purposefully avoiding anything solid state and using open knife switces to allow for student ease of viewing and comprehension, Will keep voltage below 48 VDC for now. Over that may require hot gloves.

Part of me says they gotta learn how to work hot - I guess the main dilemna for me is when I am willing to take the risk. I intend to let mistakes be part of the learning experience BUT that does NOT include meltdown, arc flash or electrocution.

If you can hold on to them for say six months and or let me know before scrapping that would be great. I will pay the freight of course and throw in the value for your favorite jug - at minimum.

Also blown up stuff would be great ie "here is commutator that is coming apart. Here is what happened and here is how ot avoid it kind of training"

Have a meter that is out of whack - error increases as you raise voltage. Neat to show how to calibrate new "working right" stuff but want to train for "this meter is out of whack - what do you think is wrong with it? Can you fix it? As an aside Branom Inst Seattle said not fixible at reasonable cost but definitely keep as training aid.

Dan Bentler

Damn babe in the basement 2 years are not going anywhere anytime soon. Some 2 or 3 hl I think the biggest 1 is maybe 15 HP. I have a few 90vdc permanent may drives as well.

Hi my name is Jeff and I am a packrat. This is my first meeting and with all of your all's support I can overcome this.

Welcome Jeff I am the moderator and Chief Pack Rat and Procurement Addicted.

I am a man
I can change
If I have to

Thank you Red Green and Possum Club.

How about dynamically braking a 6000hp main drive motor with 4 1600kW generators and a 38T flywheel

nic00 said:

How about dynamically braking a 6000hp main drive motor with 4 1600kW generators and a 38T flywheel

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I gotta be able to move this stuff to the classroom with only one guy. I assume the only power in the room is 120 VAC.

This sounds a bit heavy and big for those criteria.
Do you have a video showing this being braked and showing meter readings? That would be fantastic !!!

Dan Bentler