This manual provides the operating and maintenance procedures for the Mark II series Foxcart Ground
Power Units. The first part of this manual covers operating procedures that are typical for aircraft
Ground Power Units operating from an alternating current source. Preparation for use and routine
maintenance are also covered. The second part is addressed to trained technical personnel qualified
to perform the detailed process of electrical configuration, problem analysis and repair. Applicable
drawings, charts and schematic wiring diagrams are provided and referenced in the text to identify
components and test points with typical voltage and resistance measurements. Due to the potentially
lethal voltages, it is mandatory that the units described herein be operated and maintained by properly trained and qualified personnel only.
NOTE:The Foxcart is designed to meet Underwriter’s requirements of safety , utility and plac-
ards, even though “UL” specifications are not directed to this type of device.
-1-
PURPOSE OF EQUIPMENT
The Foxcart ground power unit is designed to provide smooth, high current DC power to aircraft
during engine starts or ground maintenance. The Foxcart, when used as an external DC source,
eliminates or minimizes excessive current drain from the aircraft’s battery and battery relay contacts.
It is also designed as a low profile unit that requires minimum ventilation and is easily moved in a
crowded hangar by one person.
-2-
MODELS
All units are provided in functional configuration with standard 15 Ft. DC cables, DC plug and 50 Ft.
AC cable with Hubbell 460P7W AC plug.
MODEL 1200
This is a single-phase power input unit and should only be considered if three-phase
power is not available. It will deliver the rated DC power, but with less efficiency and
regulation than the other models. It can handle starts on helicopters and other light
aircraft and will greatly assist a battery start on heavier aircraft.
OUTPUT VOLTS:28 VDC
PEAK DC OUT:1200 AMPS
CONTINUOUS DC OUT:600 AMPS
INPUT POWER REQUIRED:208-240 VOLTS SINGLE PHASE
200 AMPS SERVICE
MODEL 1600
This is our mid-line power unit requiring three-phase power input.
OUTPUT VOLTS:28 VDC
PEAK DC OUT:1600 AMPS
CONTINUOUS DC OUT:800 AMPS
INPUT POWER REQUIRED:208-240 VOLTS PEAK *
THREE PHASE 70 AMPS/PER PHASE
380-480 VOLTS PEAK *
THREE PHASE 50 AMPS/PER PHASE
100 AMPS SERVICE
*OTHER VOLTAGES AVAILABLE UPON REQUEST.
-3-
MODEL 2000
This is our HI-LINE unit that delivers maximum power output.
OUTPUT VOLTS:28 VDC
PEAK DC OUT:2000 AMPS
CONTINUOUS DC OUT:1000 AMPS
INPUT POWER REQUIRED:208-240 VOLTS PEAK *
THREE PHASE 100 AMPS/PER PHASE
380-480 VOLTS PEAK *
THREE PHASE 70 AMPS/PER PHASE
100 AMPS SERVICE
*OTHER VOLTAGES AVAILABLE UPON REQUEST.
60 cycle AC input current per leg at peak load for 30 seconds maximum.
MODELS
120016002000
VOL TAGESINGLE PHASE3 PHASE3 PHASE
208230115167
230218109158
240200100145
3806391
4405479
4805072
5004463
5804160
-4-
OPTIONS
1.EXTRA LENGTH OF AC CABLE
2.EXTRA LENGTH OF DC CABLELengths over 25’
not recommended.
3.SOFTSTA RTLimits Starting Current to 1100 AMPS to protect
engine starters and starter drive that require this
feature
4.SHIPPING CRATE
5.WEATHER PROOFINGExtra protection from rain and snow
6.REVERSE CURRENT DIODESPrevents aircraft batteries from draining into the
Foxcart if power is shut off and the Foxcart is not
disconnected
7.WALL BOX RECEPTACLE KITWall plug to match cable plug
8.EXTRA SIZE WHEELSFor rough terrain and snow
9.14/28 VDC SWITCHING KITUsed for starting 14 or 28-volt aircraft.
10.115 VAC UTILITY OUTLETStandard on units operating from 200-250 VAC
power source. Units operating from a higher
power source must have a step-down transformer
-5-
DESCRIPTION
The Foxcart is enclosed in an all-steel chassis frame with a three-piece steel box siding. The power
cables can be wrapped around the handles or coiled on top for storage. The wheels can be locked in
place to prevent movement. Both power cables are clamped internally to the frame for strain relief.
Location and identification of the controls are shown in Figure 2. The controls marked “optional” are
not included in the standard Foxcart unless ordered by the customer.
DIMENSIONS INCLUDING HANDLES: See FIGURE 1
STANDARD FOXCART:Length39.00”
Width21.50”
Height16.50”
WITH TERRAIN WHEELS:Length39.00”
Width21.50”
Height21.50”
-6-
PREPARATION FOR USE
The Foxcart is shipped completely assembled except for the handles. Attaching hardware is inserted into the mounting holes where the handles are to be mounted for your convenience.
Verification of Options and Strapping should be checked before use. Incorrect Primary Supply
Volt age or Strapping could cause damage or improper DC Output.
CAUTION:WHEN THE FOXCART IS PLUGGED INTO THE AC OUTLET, ALL OF THE
STRAPPING TERMINALS ARE “HOT”. CAUTION MUST BE USED TO PREVENT SHORTS OR ELECTRICAL SHOCK.
Figure 3 shows how strapping should be for different input source voltages. Select the appropriate
chart that is the same as your hangar power and compare it with the chart. If it is strapped differently correct the strapping.
The “X, Y and Z” posts are for output to the utility plug on the front of the Foxcart. To set correct
strapping, the unit must be plugged into the power source and a voltage measurement taken from
each post to case ground.
CAUTION:BEFORE RE-STRAPPING, DISCONNECT THE AC CABLE FROM THE POWER
SOURCE.
Select the post closest to 115 VAC and strap it to post “W” (See FIGURE 3)
If your Foxcart is 380 V AC or more, the Stepdown Transformer should be installed. If not, your utility
outlet voltage will be high and could cause damage to equipment.
CAUTION:TERMINALS “X AND Y” WILL BE HIGH VOLTAGE.
CAUTION:IF TERMINALS “X AND Y” DO NOT READ NEAR 115 VAC, DO NOT USE THE
UTILITY PLUG. CONTACT AUTHORIZED FACTORY REPRESENTATIVE FOR
CORRECTION.
-7-
OPERATION
1.Move the Foxcart into position and set the wheel brakes.
2.Ensure that 14/28-volt selector switch is in the same voltage range as the Aircraft. (If cart is so
equipped with this optional feature).
3.Plug the Foxcart Input Power Cable into the AC Outlet.
4.Switch the Foxcart ON/OFF breaker to “ON” and rotate the Step Switch to adjust the Voltme-
ter to the desired voltage.
5.Switch the Foxcart ON/OFF breaker to “OFF” and plug the DC cable into the Aircraft DC
receptacle.
6.Switch the Foxcart ON/OFF breaker to “ON” and re-adjust the Step Switch to the desired
voltage. Ideally, there will be no current draw until the aircraft system is activated. Some
aircraft such as early Lear Jets have a direct connection between the external connection and
the battery. An internal current draw of 100 Amperes may be observed on the ammeter of the
FOXCART. This current will decrease as the batteries are charged. On this type of Aircraft,
the batteries should be allowed to charge before energizing the Aircraft electrical system.
7.Perform normal start or maintenance.
8.After starting or completion of maintenance, switch the Foxcart ON/OFF breaker to “OFF”
and disconnect the Power Cable from the Aircraft. Move the FOXCART to a safe distance
and set the brake locks to prevent movement due to Jet or Prop blast.
SOFTSTART OPERATION
Softstart provided current limiting during engine starts to prevent over-torquing starter motors and
starter drive mechanism during starts. Use this option only if your aircraft requires it.
During a Softstart, the Foxcart produces about 20% or more of the current needed for a start and the
Aircraft batteries supply the remaining current. If the Aircraft design maintains the ship’s batteries on
line, the FOXCART will supply all the power. After start, if the FOXCART is left on line long enough,
it will recharge the Aircraft batteries.
-8-
PREVENTIVE MAINTENANCE
Routine maintenance should be performed periodically. Since the wheels and fan motor are the
only moving parts on the Foxcart, maintenance is kept to a minimum.
1.Oil fan motor and all other moveable parts.
2.Using compressed air and a dry cloth, clean accumulated dust and grime from unit.
3.Perform visual inspection and tighten any loose nuts and bolts.
4.Inspect cables and plugs for cuts, cracks or deterioration.
-9-
TROUBLESHOOTING
If the Foxcart does not deliver the proper DC output, check the strapping using the procedure
outlined on Page 7.
If the Foxcart has been operational for a period of time and has failed, use the following steps to
assist in isolating the problem. If the problem cannot be isolated, please call Foxtronics for
assistance. The phone number is (214) 358-4425. Replacement parts may be ordered from the
same number.
1.Test the wall receptacle for proper voltage.
2.Using DMM, measure the voltage at the end of the DC Cable. Does the measurement agree with for Foxcart voltmeter?
3.Remove the Strapboard Access Cover. (See Figure 2, Item 4.)
CAUTION, SHOCK HAZARD: WHEN THE INPUT CABLE IS PLUGGED INTO THE WALL
RECEPTACLE, HIGH VOLTAGES ARE PRESENT AT THE STRAPPING TERMINALS.
THESE VOLTAGES MAY BE LETHAL.
A.Plug the AC cable into wall recept acle.
B.Turn on Foxcart power.
C.Test the voltage between Terminal “A to C and “A to E” and “C to E”. All
should be the same voltage. The voltage should also be the same as your
wall voltage.
D.If step C is incorrect, the problem is between the wall and the input
strapboard.
E.Turn OFF the Foxcart power.
F.Remove the AC cable from the wall receptacle.
G.Using DMM, measure the resistance between the AC plug and the input
strapboard. All readings should be INFINITE.
H.With the AC plug still removed from the wall receptacle, turn on main
Foxcart circuit breaker. Measure resist ance between AC plug and input
strap board. Resistance should be close to zero. The ground pin should
read continuity to the Foxcart chassis.
4.If problem is still not found:
ENSURE FOXCART IS DISCONNECTED FROM THE WALL RECEPTACLE.
A.Remove top cover.
-10-
B.Inspect the interior of the Foxcart for any signs of arcing or burning, such
as wires or connections.
C.Remove rectifier bus bars and any attaching wiring.
D.Using a DMM Diode Tester , test all the diodes. All readings should be
similar in the forward direction and infinite in the reverse direction.
E.Remove buss bars and attaching wires from reverse current diodes. Test
as in step D. Note, the reverse current diodes are the opposite polarity .
F.Inspect the blue filter capacitors and wiring for leakage or burnt wires.
G.Reassemble the Foxcart.
UTILITY PLUG SET-UP
PLUG THE INPUT CABLE OF THE FOXCART INTO HANGAR POWER. USING A VOLTMETER, CHECK THE VOLTAGE AT
TERMINALS "X" AND "Y" TO CHASSIS GROUND. SELECT THE MEASUREMENT THAT IS NEAREST TO 120 VAC.
DISCONNECT HANGAR POWER, CONNECT STRAP BETWEEN SELECTED TERMINAL AND POST "W" TIGHTEN NUTS,
RECONNECT POWER AND VERIFY THAT 120 VAC IS AT THE UTILITY PLUG.
NOTE: IF INPUT AC POWER IS 380 VAC OR ABOVE AND STEPDOWN TRANSFORMER IS INSTALLED. TERMINALS W, W,
Y AND Z ARE DISCONNECTED.