Warning: Dangerous voltages may be present while performing this operation. Caution is
advised.

Note: All Z-4000’s have polarized plugs ensuring proper phase relationship when their
commons are connected.

In order to attain a proper phase relationship with older transformers either a voltmeter or a test
light (at least 18 V) is required.

Warning: Do not spark / touch the wires to test for voltage. This can cause damage to the
transformers.

1)     Disconnect all loads.

2)     Run a jumper wire (18 gauge minimum, 16 gauge preferred) between the two commons.

3)     Turn one output on each transformer to about 50 % or 12 V.

4)     Check the voltage between the two output terminals using a voltmeter or an 18 V light
        bulb. If the voltage is greater than the voltage displayed on the Z4000 then the
        two transformers are out of phase and the other transformer’s plug must be
        reversed. When using a light bulb it will burn brightly should the transformers be
        out of phase.

5)     Reverse the plug. Verify the voltage has decreased or the light has gone dim.

6)     If you started in phase you should verify by reversing the other transformer’s plug and
        observe the voltage increase or bulb getting brighter. Return the plug to attain
        proper phase relationship.

Operate the transformers in phase.

Warning: Do not operate any transformers’ outputs fully interconnected (in parallel) as this
will likely damage one of the other transformers or cause the Z-4000 to go into a
protective overload.

Caution: Failure to follow above instructions may cause damage to the Z-4000
Transformer which may not be covered under warranty. If you have any
questions, please contact our Service Department at (410) 381-2580, by fax at
(410) 381-6122, or by E-mail at Service@MTH-railking.com