Toroidal transformer power limits?
Toroidal transformer power limits?
(OP)
I'm working on a mechanical lift using DC motor powered linear actuators. The control box for the motors has a toroidal transformer which has 365W max available power according to the manufacturer.
I need to know more about the performance characteristics of such a transformer, especially how much power is available vs. demand. I assume it's not as simple as reaching the limit and then that's all there is.
I need to know more about the performance characteristics of such a transformer, especially how much power is available vs. demand. I assume it's not as simple as reaching the limit and then that's all there is.






RE: Toroidal transformer power limits?
The DC side may or may not much more limiting than the transformer itself. In the limiting case there may be a crowbar circuit that shuts down the device at 366W. Even without a crowbar circuit, the electronics are much more sensitive to overload conditions and much more willing to let go of their magic smoke.
RE: Toroidal transformer power limits?
Mfr says toroidal xfmr has 365W limit. We are not exceeding per-channel current, but apparently somehow we can not pull enough power through the motor controller.
RE: Toroidal transformer power limits?
Sounds like you need two controllers.
RE: Toroidal transformer power limits?
Thanks for your time, David.
RE: Toroidal transformer power limits?
Are you getting excess voltage drops in your supply conductors under load?
Bill
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"Why not the best?"
Jimmy Carter
RE: Toroidal transformer power limits?
Any chance you have access to a multimeter, TheTick? Some judicious measurements, carefully taken, would probably resolve this quite quickly.
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If we learn from our mistakes I'm getting a great education!
RE: Toroidal transformer power limits?
The frustrating thing is that we believed the manufacturer specs, only to find that the really stretched the truth of their system's capabilities. I think the manufacturer gambled that no one would come up with a design that would spend so much time at the top end of their envelope.
RE: Toroidal transformer power limits?
Anyone electrical work at your place? Get them to read this thread, or sign 'em up as a member if they qualify.
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If we learn from our mistakes I'm getting a great education!
RE: Toroidal transformer power limits?
Can you give us some details about the lift mechanic's of your system?
regards
desertfox
RE: Toroidal transformer power limits?
Possibly inadequate reservoir capacitors after the rectfier too"
Definitely. I was asked to help a company producing lift tables for operating rooms. Should be able to lift up to 150 kg persons.
Met specs with light load, but slowed down a lot when lifting me (not quite 100 kg, yet). It was all because the DC capacitors were too small. Adding 2200 uF was sufficient in our case.
If, however, the thermal rating is inadequate - then nothing but a blower or larger transformer works.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Toroidal transformer power limits?
Many beds have similar setups. Typically, the resulting load on the actuator decreases during lift from bottom to top, usually following a cosine curve.
My genius boss (yes, really) found a way to adjust the actuator position throughout the lift so that the actuator is able to exert nearly full force throughout the lift, maximizing lift speed. This is taxing the control box beyond its actual limits. The manufacturer admits to publishing their specs with the assumption that none of their customers would ever have a mechanism which applies a load at the top of their specs for an entire stroke of the actuator.
Meanwhile, we are trying to determine the true operating envelope of our controller/actuator system. Somehow, the control box is choking on the amount of current it needs to deliver. I am trying to gain a deeper understanding of the limiting factors.
RE: Toroidal transformer power limits?
If there is a huge drop off on voltage you will be able to add a capacitor as Skogs suggests and see if this raises the voltage appreciably. Caps are really expensive these days so the maker could certainly be skimping.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Toroidal transformer power limits?
The vendor already has a test apparatus. I think they realize that if we build our own, we will test whatever we want, including competition's stuff, without being constrained by confidentiality. At this point I can move past trying to predict the behavior of the components and concentrate on optimizing w.r.t. known system parameters.
The project is getting exciting, as I have gained some insight that will give us an advantage over our competitors, who are pursuing increased performance but looking at misleading parameters.
Thank you everyone for your input.