GAC ESD5131H Manual de inicio rápido - Página 3

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Although it is difficult to predict levels of interference, appli-

cations that include magnetos, solid sate ignition systems,

radio transmitters, voltage regulators or battery chargers

should be considered suspect as possible interfering sourc-

es.

If it is suspected that external fields, either those that are

radiated or conducted, are or will affect the governor sys-

tems operation, it is recommended to use shielded cable for

all external connections. Be sure that only one end of the

shields, including the speed sensor shield, is connected to a

single point on the case of the speed control unit. Mount the

speed control to a grounded metal back plate or place it in a

sealed metal box.

Radiation is when the interfering signal is radiated directly

through space to the governing system. To isolate the gover-

nor system electronics from this type of interference source,

a metal shield or a solid metal container is usually effective.

Conduction is when the interfering signal is conducted

through the interconnecting wiring to the governor system

electronics. Shielded cables and installing filters are com-

mon remedies.

In severe high-energy interference locations such as when

the governor system is directly in the field of a powerful

transmitting source, the shielding may require to be a spe-

cial EMI class shielding. For these conditions, contact GAC

application engineering for specific recommendations.

Instability in a closed loop speed control system can be

categorized into two general types. PERIODIC appears to

be sinusoidal and at a regular rate. NON-PERIODIC is a

random wandering or an occasional deviation from a steady

state band for no apparent reason.

The ESD5131 Sped Control Unit was derived from the stan-

dard GAC ESD5111 Speed Control Unit. All specifications,

installation procedures, and adjustments, except those not-

ed are identical.

The difference between the ESD5131 and the ESD5111 lies

in the two DIP switches located under the upper access hole.

Switch 1 controls the "Lead Circuit" found in the ESD5111.

The normal position is "ON." Move the switch to the "OFF"

position if there is fast instability in the system.

Switch 2 controls an additional circuit added in the ESD5131

that is designed to eliminate fast erratic governor behav-

ior, caused by very soft or worn couplings in the drive train

between the engine and generator. The normal position is

"OFF." Move to the "ON" position if fast erratic engine behav-

ior due to a soft coupling is experienced.

The PERIODIC type can be further classified as fast or slow

instability. Fast instability is a 3 Hz. or faster irregularity of

the speed and is usually a jitter. Slow periodic instability is

below 3 Hz., can be very slow, and is sometimes violent.

If fast instability occurs, this is typically the governor respond-

ing to engine firings. Raising the engine speed increases the

Instability

This document is subject to change without notice.

Caution: None of GAC products are flight certified controls including this item.

frequency of instability and vice versa. In this case, the re-

moval of E6 to E7 jumper will reduce the speed control unit's

sensitivity to high frequency signals. Readjust the GAIN

and STABILITY 1 or optimum control. Should instability still

be present, the removal of E1 to E2 jumper may help stabi-

lize the engine. Post locations are illustrated in Diagram 2.

Again, readjust the GAIN and STABILITY for optimum con-

trol. Interference from powerful electrical signals can also be

the cause. Turn off the battery chargers or other electrical

equipment to see if the system instability disappears.

Slow instability can have many causes. Adjustment of the

GAIN and STABILITY usually cures most situations by

matching the speed control unit dynamics. If this is unsuc-

cessful, the dead time compensation can be modified. Add

a capacitor from posts E2 to E3 (negative on E2). Post lo-

cations are illustrated in Diagram 2. Start with 10 mfds, and

increase until instability is eliminated. The control system

can also be optimized for best performance by following this

procedure.

If slow instability is unaffected by this procedure, evaluate

the fuel system and engine performance. Check the fuel

system linkage for binding, high friction, or poor linkage. Be

sure to check linkage during engine operation. Also look at

the engine fuel system. Irregularities with carburetion or fuel

injection systems can change engine power with a constant

throttle setting. This can result in speed deviations beyond

the control of the governor system. Adding a small amount

of droop can help stabilize the system for troubleshooting.

NON-PERIODIC instability should respond to the GAIN con-

trol. If increasing the gain reduces the instability, then the

problem is probably with the engine. Higher gain allows the

governor to respond faster and correct for disturbance. Look

for engine misfirings, an erratic fuel system, or load changes

on the engine generator set voltage regulator. If the throttle

is slightly erratic, but performance is fast, removing the jump-

er from E6 to E7 will tend to steady the system.

If unsuccessful in solving instability, contact GAC for assis-

tance.

PIB1000 C