CH DC WIAD Controller used with other power supplies

Are there any threads on PM detailing use of the CH DC Controller from a WIAD machine with an aftermarket DC power supply? If not, have any of you integrated the CH DC controls from a WIAD machine with a more modern DC power supply and would you share some of the details? Some of it seems pretty straight forward, such as use of the FWD/REV contactors and the DC control circuit, but do the AP and FL relays in the CH controller and the big resistors for a rapid slow down when reversing or stopping the machine serve a useful purpose with a more modern DC supply? Condition of the control is not a factor here, for the purpose of the question assume the CH control is in excellent working condition.

I don't know anything about the CH DC controls, but I do know about DC power supplies. If my assumption of "CH DC controls" is correct, you're looking to just put a DC power supply in front of the "CH DC controls"?

I'm using an off the shelf Meanwell 250VDC, 3000W supply with my custom PWM controller (CSP - 3000 - 250). It's borderline too small for full power from the 3HP large frame motor, but I don't expect to ever push the machine anywhere close to full power. But, if I ever do need more power, it's designed to be paralleled up to 3x (9000W). Cost is about $450 if I remember right.

For basic DC supply like this, the braking resistor is definitely still necessary. A modern, fully integrated 4-quadrant supply+control would push this energy back onto the line. But you're not going to get 4-quadrant control with a general purpose DC supply like this. It can only source power. It can't sink back to the line. The braking resistor is necessary to dump the mechanical energy to heat for rapid stops. I'm not aware of any reasonable cost DC supply that can source and sink. They definitely exist but, at this power level, you're talking many thousands $$$$ vs. a few hundred for sourcing only like the Meanwell.

You will also still need AP and FL relays. AP (anti-plugging) relay will prevent reversing at wrong time (i.e. prevent operation in a quadrant that the DC supply really won't like). FL (Field Loss) relay will protect the motor from, well, loss of field current.

Here's thread on my custom PWM controller. Note that this one does away with AP and FL relays (it's handled in controller logic), but still will require a braking resistor for rapid deceleration.
PWM Drive for DC Motor

Greg

rimcanyon said:

Are there any threads on PM detailing use of the CH DC Controller from a WIAD machine with an aftermarket DC power supply? If not, have any of you integrated the CH DC controls from a WIAD machine with a more modern DC power supply and would you share some of the details? Some of it seems pretty straight forward, such as use of the FWD/REV contactors and the DC control circuit, but do the AP and FL relays in the CH controller and the big resistors for a rapid slow down when reversing or stopping the machine serve a useful purpose with a more modern DC supply? Condition of the control is not a factor here, for the purpose of the question assume the CH control is in excellent working condition.

Click to expand...

Just to avoid confusion, you're talking about the DC Control Panel (the big box with all the relays, located near the spindle motor). As you probably know, the DC Control Panel used by WiaD (Work in a Drawer) and square-dial motor/generator (MG) machines are very similar. Both panels use the same Cutler-Hammer relays. The main differences appear to be that the WiaD panel has a few extra terminals at the bottom, to support things like the WiaD's separate spindle motor series field windings, and it doesn't have the three resistors in the upper-right corner (some have two, some have none).

In both the WiaD and MG drives, the drive itself (that is, the stuff outside the DC Control Panel) provides a variable armature supply and a variable field supply. The DC Control Panel provides the following functions:

• reversing
• forward/reverse interlocking
• field acceleration
• anti-plugging
• dynamic braking

The drives provide:

• field and armature control
• field weakening
• field loss protection

I don't know how the WiaD drive handles field loss protection. For MG machines field loss protection is incomplete.

There are a couple of MG DC control panels being used in conjunction with solid state DC drives. The ones that I'm thinking about use the big Ohmite "Motor" rheostat to handle the field weakening, so only one solid state drive is needed. I don't know of anyone using a WiaD panel that way, but there's no reason that it couldn't be done.

Basically, the WiaD DC panel has a nice, interlocked pair of forward/reverse contactors (relays) that include the arc chutes and blowout coils needed to interrupt large DC currents, and include contacts that provide automatic dynamic braking. It also provides a dual-winding Field Accelerartion (FA) relay, an Anti-Plugging (AP) relay and an overload device to protect the spindle motor's armature. With that, a suitable rheostat (the rheostat from a WiaD machine is ideal) and two, single-quadrant solid state DC supplies you could build a nice 10EE motor controller.

Cal

MG machines don't handle a field loss due to a break in the "Motor" rheostat windings. We had one show up fairly recently and it caused some real problems.

Peter.'s machine is a 1942 round-dial with a DC panel that uses Struthers-Dunn relays (link). So, not a WiaD panel, sorry.

Cal

Everybody is getting off track here. I really need to know if the combination of parts I already have is going to work, I'm not looking for alternatives. i.e. think of it this way:

If I had a mid-50's WIAD machine, and wished to replace the WIAD with a DC power supply, could I do it simply? I want to keep the DC controller, the 5HP motor with gearbox, and I have all the control circuitry already installed (110V AC and 110V DC). I'm assuming some familiarity with Monarch wiring and circuitry.

So I would appreciate if the discussion stays closer to the original questions.

I'll be the first to admit I haven't analyzed the schematics for a 10EE in depth, but dumbing it down to the most basic level -
I think the issue is that the DC controller in the Monarch is not just a simple constant voltage DC power supply in front of some other circuitry. A lot of modern (digital) equipment runs with a straight constant voltage power supply feeding power to a piece of equipment (like a computer or flat screen TV).

Running a large DC motor, it makes more sense to have a variable voltage supply based on what is needed by the motor/RPM combination. Otherwise you end up using something like resistance to dissipate voltage. That gets to be very inefficient at the power levels needed by a 10EE, so instead it gets into a more complex feedback between the operating conditions and the voltage level output by the DC controller.

(duplicated post for some weird reason)

thermite said:

...
Seems I am not he who may even venture an opinion, these days?
...

Click to expand...

Bill,

If that's directed at me, your opinions are welcome here. You have a huge storehouse of knowledge and the potential to be a real asset to the Monarch community. I have no doubt that you're much smarter than me and probably better looking as well.

The problem comes when your opinions overwhelm the discussion and you defend your points with all the subtly of an orbiting AC-130. Your long, frequent posts to certain threads are very off-putting to others and tend to crush the discussion. I'm a little like that myself, which is why I take a long time with my posts, reading and re-reading before posting, trying to be clear, concise and asking myself how others will react to my words. I assume that everyone is either having a bad day or easily offended, and try to write accordingly. Also, bear in mind that a lot of working stiffs can't be online very often, so if a thread has been overrun in the meantime, they might be less likely to chime in, even though they may have some very good insights to share.

We have a new set of rules for a reason. The support for rules, as expressed during the comment period (link), appears unanimous. I regret that you didn't take part in that discussion. But you seem to be in open defiance of the new rules and that's putting me in a tough spot.

For the record, I have nothing against you personally. You have helped me off-line. You have publicly supported me and complimented the job I was doing as a moderator. In fact, you helped clear the way for me to become moderator when PeterH "retired", both by nominating me and by putting me in contact with Milacron when normal channels failed.

What do you say we both make an effort to help people, be good citizens of the Monarch Forum and work within the new rules?

Cal