Telma retarder power supply options?
I´m renovating at the moment two Telma CC160 retarders and now charting options of power supplies.
Going to use them as hub dynos, so both need own power supply.
Sportdevices has two different kind:
Brake Power Supply PWS3.2
Note 2: HS-PWS does NOT include the fast discharge feature (HS-PWS-D) this product is in the final tests stage about to start production phase
What does that mean?
I have searched aliexpress etc. but is there any usable options?
The two SportDevices power supplies are very good and they work equally good. The HS-PWS-D is a new version that is not released yet. It includes a feature to discharge the current in the Telma fast when you suddenly turn off the brake. The point with that is the following: At the end of the run when you want to start the retardation phase, ideally the Telmas should turn off very quickly, otherwise it looks like there is a lot of transmission loss at that point. Normal power supplies are quite slow to turn off due to the Telmas having a high inductance. Burning off that power faster is possible with a big power resistor and that is what the HS-PWS-D is doing.
Anyway, YourDyno ignores the first 2 seconds of the retardation phase to get around this common problem. The retardation follows a mathematical formula pretty well, so ignoring the first 2 seconds is no problem unless your retardation phase is very very short.
SportDevices is the only off-the-shelf power that I know of. But there are many options if you want to build one. Check out this option, it is tried and simple: https://yourdyno.com/YourDynoHelp/maha-chassis-dyno-retofit/ Make sure you know what you're doing if you go this route.
The spec looks good.
There is no mention of the speed of the regulator. Some power supplies are slow by design (but you can typically turn off the slow start). That part is probably ok, but worth asking if you go this route. You should also ask if it can drive an inductive load (like a DC motor). When you turn off fast the current will continue to flow in the Telma, which the power supply must support, otherwise you need an external power diode (with cooling).
It could be ok, nothing wrong from the spec. But it is almost the cost of the SportDevices option.
One question, if i wire new coils to series, how i check the polarity? With compass, or is there any difference how i connect them...?
E: Second question, how can i add picturelinks here?
You will need to wire them like described in the bottom of this document.
Plus and minus of the total system does not matter, but they need to be wired so they alternate North-South as you can see.
The crimps of the coil wires are color coded, but if you are unsure you can use a compass and test one magnet at the time.
You can attach a file or just link to pics on some other place.