WTS, 235/320/360/Legacy Hydraulic Pump Controller

[Paul Miller]

I'd better upgrade my 1N4001s

IN4001 cockpit accessory

[Chris Zavatson]

... the back EMF current on these motors ranges from about 10 to 60A depending on the load at the time power is pulled.

I guess I'd better upgrade my 1N4001s then, shouldn't I.

John,
I assume you have those on the relay coils.
In that case, you are not protecting against the much larger motor coil, but then you really have no need to. That just produces an arc at the relay contacts. Your diodes are protecting the more sensitive pressure switch contacts.

[Louis Gabriel]

I guess I'd better upgrade my 1N4001s then, shouldn't I.

The 1N4001 is rated at 50V/1A, and I had a similar diode fail (shorted closed, taking the gear control system with it). Mine was a 60V/5A diode, SB560-E3, called for by the VP-X installation manual.

After talking it over with Chris, I now have 400V/1A flyback diodes and no problems. Suggest 1N4004 or similar.

[John Cooper]

I assume you have those on the relay coils.

No, they''re from the motor wires to ground and have been working fine so far. I know this because my transition light LED is hooked to those wires (through isolation diodes and fuses) and if the snubbing diodes are not there, the transition LED will burn out due to the counter EMF spike. (Ask me how I know.) Actually, I think my snubbing diodes are 1N4007, but I'll upgrade them for more current anyway.

[Steve Colwell]

Hey Chris, I'm in, what is your mailing address and when do you want payment? Steve Colwell Legacy

[Chris Zavatson]

I assume you have those on the relay coils.

No, they''re from the motor wires to ground and have been working fine so far. I know this because my transition light LED is hooked to those wires (through isolation diodes and fuses) and if the snubbing diodes are not there, the transition LED will burn out due to the counter EMF spike. (Ask me how I know.) Actually, I think my snubbing diodes are 1N4007, but I'll upgrade them for more current anyway.

Are you hooked up directly to the motor wires? The solenoids most are using (or used to use) have a tap (labeled "I") for indicating voltage on the contactor disc in the solenoid. As soon as it lifts off there is no connection to either input or output terminals.

[John Cooper]

Are you hooked up directly to the motor wires?

Close. The diodes and bigazz MOVs are connected to the relay outputs. I decided decades ago not to use those 1930's technology, heavy, solenoids. I'm still using the Bosch relays. (Diodes not shown but they are in parallel with the MOVs.

[Chris Zavatson]

John,
Here is one of the Back EMF plots. This is on the higher end (even with a somewhat slow sampling rate) with a motor at PRV pressure rather than pressure switch pressure. The 1N4007 absolute rating is on the order of 30A for 5ms. Your MOVs are probably taking the edge off.

[Paul Miller]

i received my controller this week, very impressive, light. The instructions are included. I don't know if a metal enclosure is a better choice (for fire protection) but it would be easy enough to swap enclosures with four screws on the circuit board. You will have to modify for your cable setup. I will post when I get to installation.

[Mark Davis]

I too have received my new hydraulic pump controller from Chris and Louis. It appears to be a very high quality product in a very complete package right down to the crimp terminals need for installation. Illustrated installation instructions included with the controller. Will post again after installation (may be a while) with results.