Jet Pump Tripping Due to Rain

7/17/2019 Jet Pump Tripping Due to Rain

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CAUSES OF TRIPPING OF JET

PUMPS IN RAINY CONDITION

Presented By:

Shahid Rabbani

Electrical Technician



JET PUMP PROTECTIONS

• 1. low/high oil level of pump, gear box and

engine.

• 2. Vibration protection of pump and engine

• 3. Force lubrication

• 4. Jacket water coolant level



PROTECTION SCHEME

• Jet pump control and protected by mostly

Murphy controller TTD.

• 2 types of protection is allowed by TTD,

A- CLOSED LOOP OR NORMALLY CLOSED

CONTACT

In this scheme protective device ( like PSL switch) provide

normally close contact as it operate TTD will shutdown the

machine. PSL switches are sealed and weather proof.



B. SINGLE WIRE PROTECTION

SCHEME

In this scheme protective device (like oil level

GLG, vibration switches etc.) uses normally open

contact but on side of contact connected to

ground and 2nd side from TTD. As device operate

contact closed to ground and TTD shutdown the

machine.



CLOSE LOOP CIRCUIT

TTD

N.C



OPEN LOOP CIRCUIT

TTD

N.O Contact of OIL level

GLG,Viberation switches etc.



POSSIBLE CAUSES OF FAILURE/

TRIPPING

• 1- Actual operation/ actual fault

• 2- Malfunctioning / false tripping



CAUSES OF MALFUNCTIONING / FALSE

TRIPPING

1- Ingress of water .2- Ingress of salted dust (mist)

3- Wire Insulation failure due to high

temperature (rarely)4- Wire insulation breakdown due to mechanicalinjury.

5- polluted or moisturized oil that’s respond aslow resistance path (in oil level GLG)

6- TTD faults.



• Faults due to Ingress of water or mist/dust

are approx. 80% of total false tripping.

• 15% false tripping due to wire insulation

failure or due to moisturized oil.

• 5% false tripping is TTD faults, (relay

malfuntioning,TTD connector strip rusted or

any other wire termination related)



RECOMMENDATIONS

• We can save 80% false tripping to protect

from water or rain.

• Charging Alternator are commonly and

repeatedly failure reported due to rust or mist

reaction.



RECOMMENDATIONS

•

Installation of shed on jet pump full skid.• Replacing weatherproof switches with

existing.

• Covering with polythene or fiber glassindividually switches

• Or properly sealed with RTV/silicone onexisting switches (but not durable and

moisture can trap inside and during hightemperature its can rupture and provides pinholes to ingress of moisture or water.



SHED



WEATHER PROOF GLG



NON CLASSIFIED GLG



ALTERNATOR FALIUREBATTERY CHARGER ALTERNATOR NON

CLASSIFIED



NON CLASSIFIED LUBRICATOR FLOAT

SWITCH



NON CLASSIFIED

VIBRATION SWITCH



NON CLASSIFIED

WATER LEVEL SWITCH



WEATHERPROOF LUBRICATOR FLOAT

SWITCH



WEATHERPROOF FUEL GAS SCRUBBER

LSH SWITCH



WEATHERPROOF

VIBRATION SWITCH



THANK YOU

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Jet Pump Tripping Due to Rain