Submersible Pump Amps Too High? 12 Causes And Practical Fixes
When Submersible Pump Amps Are Too High, The Most Common Causes Are Low Voltage, Excessive Flow, Phase Imbalance, Incorrect Wiring, A Defective Capacitor, Sand Blockage, Mechanical Drag, Or Motor-Winding Damage. Compare The Measured Running Current With The Motor Nameplate Before Adjusting Protection Settings Or Pulling The Pump.
High Motor Current Should Never Be Ignored. Continued Operation Above The Manufacturer’s Permitted Current Can Overheat The Windings, Damage The Drop Cable, Trip The Overload Relay, Reduce Motor Efficiency, And Eventually Cause Complete Pump Failure.
What Does High Amperage Mean On A Submersible Pump?
Amperage Represents The Electrical Current Used By The Submersible Motor.
The Motor Usually Draws A High Starting Current For A Short Time During Acceleration. After Reaching Normal Speed, The Current Should Stabilize Within The Manufacturer’s Permitted Operating Range.
A High-Amp Problem Exists When:
- Running Current Exceeds The Motor Nameplate Limit
- One Phase Draws More Current Than The Other Phases
- Current Continues Increasing During Operation
- The Overload Relay Frequently Trips
- Starting Current Remains High Because The Motor Cannot Accelerate
- Measured Current Is Significantly Higher Than The Original Commissioning Data
Always Distinguish Between Starting Current, Full-Load Current, And Service-Factor Current. Their Definitions And Permitted Duration Depend On The Specific Motor.
What Is The Normal Amp Draw For A Submersible Pump?
There Is No Universal Normal Amperage For Every Submersible Pump.
Normal Current Depends On:
- Motor Power
- Supply Voltage
- Single-Phase Or Three-Phase Design
- Motor Efficiency
- Power Factor
- Pump Flow Rate
- Total Dynamic Head
- Water Density
- Cable Length
- Voltage At The Motor
- Motor Load
- VFD Output Frequency
For Example, Two Motors With The Same 5 HP Rating Can Have Different Full-Load Current Values Because They Operate At Different Voltages Or Have Different Efficiencies.
Use These References In This Order:
- Motor Nameplate
- Motor Manufacturer’s Data
- Pump Performance Curve
- Control-System Manual
- Original Commissioning Measurements
- Current Operating Measurements
Do Not Use A Generic Online Amp Chart As A Replacement For The Actual Motor Nameplate.
High Starting Amps Vs High Running Amps
| Current Condition | What It Usually Means | Recommended Action |
|---|---|---|
| High Current For A Short Time During Start | Normal Motor Acceleration May Be Occurring | Compare With Manufacturer Starting Data |
| High Current With No Acceleration | Locked Rotor, Low Voltage, Failed Capacitor, Or Incorrect Wiring | Stop The Motor And Test The Starting Circuit |
| Normal Starting Current But High Running Current | Hydraulic Overload, Mechanical Drag, Or Voltage Problem | Measure Flow, Pressure, Voltage, And Phase Current |
| Current Gradually Increases | Heating, Falling Voltage, Mechanical Tightening, Or Sand Accumulation | Stop And Inspect Before The Overload Trips |
| One Phase Has High Current | Phase Imbalance, Loose Connection, Or Winding Damage | Measure All Phase Voltages And Currents |
| High Current Only At Certain VFD Speeds | Incorrect Drive Settings, Resonance, Or Excessive Load | Review Drive Programming And Pump Curve |
Repeatedly Starting A Motor That Cannot Accelerate Can Rapidly Damage The Motor Windings, Cable, Control Box, And Starting Components.
What Are The Most Common Causes Of High Submersible Pump Amps?
1. Low Supply Voltage
Low Voltage Is One Of The Most Common Causes Of Excessive Motor Current.
When The Motor Receives Insufficient Voltage, It May Draw More Current To Produce The Required Torque. This Increases Winding Temperature And Can Cause Overload Trips.
Possible Causes Of Low Voltage Include:
- Undersized Power Cable
- Excessive Cable Length
- Loose Electrical Connections
- Burned Contactor Contacts
- Weak Transformer Capacity
- Unstable Generator Output
- Excessive Voltage Drop
- Incorrect Supply Voltage
- Damaged Drop Cable
- Poor Underwater Cable Splice
Measure Voltage With The Pump Off And Again While It Is Starting And Running. A No-Load Voltage Reading May Look Normal Even When The Voltage Drops Excessively Under Motor Load.
Install Appropriate Submersible Pump Voltage Protection To Monitor Undervoltage, Overvoltage, Phase Loss, And Voltage Imbalance.
2. Excessive Pump Flow
A Multistage Centrifugal Deep Well Pump May Draw More power When It Operates At A Higher Flow Rate Than Its Designed Duty Point.
This Can Happen When:
- System Resistance Is Lower Than Expected
- Discharge Pressure Is Too Low
- A Control Valve Is Fully Open
- The Selected Pump Produces Too Much Flow
- The Actual Total Dynamic Head Is Lower Than The Design Value
- A Check Valve Fails To Maintain Backpressure During Starting
- The Pump Operates Too Far To The Right Of Its Performance Curve
The Grundfos High Motor Current Explanation Identifies Undervoltage, Current Imbalance, Incorrect Wiring, Blockage, Motor Faults, And Operation Above Nominal Flow As Possible Causes.
For A Centrifugal Pump, A Technician May Briefly Throttle The Discharge Valve To Determine Whether Current Falls As Flow Decreases. Perform This Test Only When The Pump Manufacturer Allows It.
Never Operate The Pump Against A Completely Closed Valve For An Extended Period. Low-Flow Operation Can Cause Heating, Unstable Hydraulic Forces, And Bearing Damage.
3. Incorrect Total Dynamic Head
A Pump Selected For The Wrong Head Can Operate Outside Its Recommended Performance Range.
Total Dynamic Head Includes:
- Vertical Lift
- Required Discharge Pressure
- Pipe Friction Loss
- Valve And Fitting Loss
- Filter Loss
- Elevation Difference
- Pressure-Tank Requirements
Use This Simplified Formula:
TDH = Vertical Lift + Pressure Head + Friction Losses
For Water:
Pressure Head In Meters ≈ Pressure In Bar × 10.2
If The Actual Head Is Much Lower Than Expected, A Centrifugal Pump May Produce Excessive Flow And Draw High Current. If The Head Is Excessively High, Flow May Become Too Low And The Pump Can Operate Outside Its Permitted Range.
Review The Total Dynamic Head For Submersible Pump Before Changing The Pump Or Motor Size.
4. Sand Or Sediment Inside The Pump
Sand, Silt, Scale, And Mineral Deposits Can Increase Mechanical Resistance Inside The Pump.
Abrasive Material Can:
- Jam The Impellers
- Increase Bearing Friction
- Reduce Internal Clearances
- Damage Diffusers
- Wear The Pump Shaft
- Block The Suction Screen
- Increase Starting Torque
- Cause Current Fluctuation
A Sand-Damaged Pump May Show High Current Together With Reduced Flow, Vibration, Noise, Or Frequent Overload Trips.
If The Well Produces Sand, Correct The Well Condition Before Installing A Replacement Pump. Otherwise, The New Pump May Develop The Same Problem.
5. A Worn Or Blocked Pump
A Pump With Damaged Internal Components May Require More Torque From The Motor.
Possible Mechanical Problems Include:
- Seized Radial Bearing
- Damaged Thrust Bearing
- Bent Shaft
- Misaligned Pump And Motor
- Debris Between Rotating Components
- Worn Impeller
- Damaged Diffuser
- Tight Mechanical Seal
- Corroded Components
- Failed Pump-To-Motor Coupling
A Blocked Pump Usually Produces High Current, Low Flow, Or No Flow. A Severely Worn Pump May Produce Low Pressure Even When Current Appears Normal.
Electrical And Hydraulic Data Should Be Evaluated Together Before The Pump Is Removed.
6. Three-Phase Voltage Or Current Imbalance
A Small Voltage Imbalance Can Produce A Much Larger Current Imbalance In A Three-Phase Motor.
Possible Causes Include:
- Unequal Phase Voltage
- Loose Terminals
- Burned Contactor Contacts
- Poor Cable Splice
- Damaged Conductor
- Incorrect Transformer Connection
- Unbalanced Single-Phase Loads
- Motor-Winding Damage
- Phase Loss
Measure All Three Line-To-Line Voltages And All Three Phase Currents Under Load.
Use This Formula:
Current Imbalance (%) = Maximum Deviation From Average Current ÷ Average Current × 100
Assume The Three Current Measurements Are:
- Phase A: 12.1 A
- Phase B: 12.5 A
- Phase C: 13.4 A
The Average Current Is:
Average Current = (12.1 + 12.5 + 13.4) ÷ 3 = 12.67 A
The Maximum Deviation Is:
13.4 − 12.67 = 0.73 A
Therefore:
Current Imbalance = 0.73 ÷ 12.67 × 100 = 5.76%
Compare The Result With The Motor Manufacturer’s Limit. Do Not Apply A Universal Imbalance Limit To Every Motor.
7. Incorrect Motor Wiring
Incorrect Wiring Can Cause Excessive Current Immediately After Installation Or Maintenance.
Common Wiring Errors Include:
- Wrong Star Or Delta Connection
- Incorrect Motor Voltage
- Reversed Or Misidentified Motor Leads
- Loose Terminal Connections
- Incorrect Control-Box Connection
- Wrong Start And Run Capacitor Wiring
- Incorrect Transformer Tap
- Improper Contactor Configuration
- Wrong Motor Selected In The VFD
Check The Wiring Against The Diagram Supplied With The Exact Motor And Controller.
A Connection That Appears Correct For One Motor May Be Wrong For Another Motor With The Same Power Rating.
8. Defective Start Or Run Capacitor
Single-Phase Three-Wire Submersible Motors Commonly Use An External Control Box Containing Starting Components.
A Failed Capacitor Or Relay Can Cause:
- High Starting Current
- Motor Humming
- Slow Acceleration
- Repeated Overload Trips
- Failure To Start
- Excessive Winding Temperature
- Burned Relay Contacts
Inspect The Electric Control Box For Submersible Pump For Swollen Capacitors, Burned Terminals, Loose Connections, Failed Relays, And Incorrect Component Ratings.
Capacitors Can Retain Dangerous Electrical Energy After Power Is Disconnected. Testing Should Be Performed By A Qualified Technician Using The Manufacturer’s Discharge Procedure.
9. Damaged Motor Windings
Shorted Or Deteriorated Windings Can Increase Current And Motor Temperature.
Possible Warning Signs Include:
- Unbalanced Winding Resistance
- Low Insulation Resistance
- High Current On One Or More Phases
- Repeated Breaker Trips
- Burned Odor At Surface Components
- Overload Trips After A Short Running Period
- Reduced Motor Torque
- Abnormal Starting Behavior
Measure Winding Resistance Only After Disconnecting And Locking Out The Power.
A Surface Resistance Test Includes The Motor Windings, Submersible Pump Cable, And Cable Splices. It May Confirm A Downhole Circuit Problem Without Identifying The Exact Failed Component.
10. Incorrect VFD Settings
A Variable Frequency Drive Must Be Programmed For The Connected Motor And Pump.
Incorrect Parameters Can Cause High Current Because Of:
- Wrong Motor Voltage
- Incorrect Rated Current
- Incorrect Base Frequency
- Excessive Acceleration Rate
- Inadequate Minimum Frequency
- Incorrect Motor Type
- Improper Control Mode
- Excessive Torque Boost
- Incorrect Carrier Frequency
- Pump Operation Outside Its Curve
- Excessive Motor-Cable Length
- Missing Output Filter Or Reactor When Required
Review The Variable Frequency Drive For Submersible Pump Before Changing Drive Parameters.
Standard Multimeters May Not Accurately Measure PWM Voltage At The VFD Output. Use Drive Diagnostics Or A VFD-Compatible Analyzer.
11. Pumping Liquid With High Density Or Viscosity
Submersible Well Pumps Are Commonly Rated For Clean Water.
A Liquid With Higher Density Or Viscosity Can Increase Motor Load. This May Occur In:
- Industrial Process Water
- Water With High Solids Content
- Sludge
- Chemical Solutions
- High-Salinity Water
- Thick Wastewater
- Water Containing Heavy Sediment
The Pump Materials May Also Be Incompatible With The Liquid.
Provide The Manufacturer With The Liquid Density, Viscosity, Temperature, pH, Solid Size, And Solid Concentration Before Selecting The Pump.
12. Incorrect Pump And Motor Matching
The Pump And Motor Must Be Matched For The Entire Operating Range, Not Only For One Nominal Duty Point.
High Current Can Occur When:
- The Pump Requires More Power Than The Motor Can Supply
- Too Many Pump Stages Are Connected To The Motor
- The Motor Power Is Incorrect
- The Pump Curve Extends Beyond The Motor Rating
- A 50 Hz Pump Is Operated Incorrectly On 60 Hz
- The Wrong Motor Is Selected In A VFD System
- Impeller Trimming Or Stage Configuration Is Incorrect
Check The Maximum Pump Power Across The Allowed Flow Range. The Motor Should Be Selected According To The Manufacturer’s Published Performance Data And Service-Factor Requirements.
How Do You Diagnose High Amps Step By Step?
Follow A Structured Diagnostic Sequence Instead Of Replacing Parts Based On One Current Reading.
Step 1: Record The Nameplate Data
Record:
- Motor Power
- Rated Voltage
- Rated Current
- Service-Factor Current
- Frequency
- Phase
- Connection Method
- Duty Rating
- Motor Model
- Pump Model
Step 2: Measure Current In Every Conductor
Use A Properly Rated Clamp Ammeter. Record Current During Starting And Stable Operation.
For A Three-Phase Motor, Measure All Three Phases. One Reading Is Not Enough.
Step 3: Measure Voltage Under Load
Measure Voltage Before Starting And While The Pump Is Running. Check The Incoming Supply, Contactor Output, And Other Accessible Test Points.
Step 4: Check Flow And Pressure
Measure Actual Flow And Discharge Pressure At The Same Time As Motor Current.
Review The Submersible Pump Flow Rate To Determine Whether The Pump Is Operating Above Its Rated Capacity.
Step 5: Compare The Duty Point With The Pump Curve
Plot The Measured Flow And Calculated Head On The Manufacturer’s Pump Curve.
Confirm That The Duty Point Is Inside The Recommended Operating Range.
Step 6: Perform A Controlled Throttling Test
When Permitted By The Pump Manufacturer, Slightly Reduce Discharge Flow And Observe The Motor Current.
| Test Result | Likely Meaning |
|---|---|
| Current Falls As Flow Is Reduced | Pump May Be Operating At Excessive Flow Or Low Head |
| Current Remains High | Electrical Or Mechanical Problem Is More Likely |
| Current Fluctuates Rapidly | Water-Level Instability, Cavitation, Or Loose Connection May Exist |
| Pressure Rises But Flow Does Not Change Correctly | Gauge, Valve, Pipe, Or Hydraulic Damage May Be Present |
This Test Is A Diagnostic Step, Not A Permanent Solution. Confirm The Correct Operating Range Before Adjusting The System.
Step 7: Test Winding And Insulation Resistance
Disconnect The Motor Circuit From The Controller, VFD, Capacitors, And Sensitive Electronics.
Measure:
- Phase-To-Phase Resistance
- Lead-To-Lead Resistance
- Each Lead To Ground
- Insulation-Resistance Trend
Use The Test Voltage And Acceptance Criteria Specified By The Motor Manufacturer.
Step 8: Inspect The Control And Protection System
Check:
- Overload Setting
- Trip Class
- Contactor Condition
- Fuse Size
- Circuit-Breaker Rating
- Phase-Loss Protection
- Voltage-Protection Settings
- Dry-Run Protection
- VFD Fault History
- Starting Frequency
- Acceleration Time
Should You Increase The Overload Setting?
Do Not Increase The Overload Setting Simply To Stop Nuisance Trips.
The Overload Device Protects The Motor From Excessive Current And Heat. Raising Its Setting Without Correcting The Cause Can Allow The Motor To Burn.
The Protection Setting Should Follow:
- Motor Nameplate Data
- Motor Manufacturer’s Instructions
- Starter Manufacturer’s Instructions
- Service-Factor Requirements
- Applicable Electrical Regulations
- Actual Installation Conditions
The Submersible Pump Overload Protection Should Disconnect The Motor Before Excessive Current Causes Permanent Thermal Damage.
Franklin Electric’s AIM Manual Resources Provide Manufacturer-Specific Application, Installation, And Maintenance Information For Submersible Motors.
Can An Undersized Cable Cause High Amps?
Yes. An Undersized Or Excessively Long Cable Can Create Voltage Drop At The Motor.
The Surface Supply Voltage May Be Correct While The Motor Receives Lower Voltage Because Of Cable Resistance.
Cable Selection Should Consider:
- Motor Full-Load Current
- Starting Current
- Supply Voltage
- Cable Length
- Installation Temperature
- Conductor Material
- Permitted Voltage Drop
- Local Electrical Requirements
- VFD Compatibility
- Submersible Cable Certification
Increasing The Overload Setting Does Not Correct An Undersized Cable.
Can A Bad Check Valve Cause High Current?
A Leaking Or Missing Check Valve Can Remove The Static Water Column That Normally Provides Backpressure During Restart.
This May Allow The Pump To Start At An Abnormally High Flow Rate. Depending On The Pump Curve, Current And Hydraulic Thrust Can Increase.
A Check-Valve Problem May Also Cause:
- Reverse Rotation
- Water Hammer
- Frequent Cycling
- Delayed Pressure
- Pipe Movement
- Repeated Starting Wear
Inspect The Valve And Observe Pressure Decay After The Pump Stops.
When Should The Pump Be Pulled From The Well?
Pump Removal May Be Necessary When Testing Indicates:
- A Locked Pump
- Persistent Mechanical Drag
- Sand Blockage
- Damaged Pump Bearings
- A Broken Coupling
- Motor-Winding Failure
- Low Insulation Resistance In The Downhole Circuit
- A Damaged Drop Cable Or Underwater Splice
- High Current That Remains After Surface Faults Are Eliminated
- Severely Reduced Hydraulic Performance
- Abnormal Noise Or Vibration
Do Not Pull The Pump Until Accessible Components Have Been Checked. A Defective Pressure Switch, Capacitor, Contactor, VFD Setting, Valve, Or Surface Connection Can Produce Similar Symptoms.
High-Amp Diagnosis By Current Pattern
| Current Pattern | Probable Causes |
|---|---|
| High Current On All Phases | Low Voltage, Excessive Flow, Mechanical Overload, Or Incorrect Motor Selection |
| High Current On One Phase | Loose Connection, Supply Imbalance, Cable Fault, Or Winding Damage |
| High Current And Low Flow | Blockage, Mechanical Drag, Sand, Or Incorrect Rotation |
| High Current And High Flow | Pump Operating At Excessive Flow Or Insufficient Head |
| High Current And Normal Flow | Voltage Problem, Motor Damage, Or Mechanical Friction |
| Current Increases As Pump Runs | Heating, Falling Voltage, Sand Accumulation, Or Tightening Components |
| High Current At Start Only | Normal Acceleration Or A Developing Starting Problem |
| High Current With No Water | Locked Pump, Broken Coupling, Blocked Pipe, Or Dry-Well Condition |
| Low Current And No Water | Dry Running, Broken Pipe, Or Failed Coupling |
| Rapidly Changing Current | Unstable Water Level, Cavitation, Loose Wiring, Or VFD Instability |
What Information Should Be Sent To The Pump Manufacturer?
Provide The Following Information For Accurate Diagnosis:
- Pump Model
- Motor Model
- Motor Power
- Nameplate Voltage
- Nameplate Current
- Service-Factor Current
- Supply Frequency
- Single-Phase Or Three-Phase Power
- Current On Every Conductor
- Voltage Before Starting
- Voltage During Starting
- Running Voltage
- Static Water Level
- Dynamic Water Level
- Pump Installation Depth
- Measured Flow Rate
- Measured Pressure
- Calculated Total Dynamic Head
- Drop-Cable Size And Length
- Control-Box Model
- VFD Model And Settings
- Winding-Resistance Results
- Insulation-Resistance Results
- Water Temperature
- Sand Content
- Fault Codes
- Number Of Starts Per Hour
This Information Helps Separate Electrical Problems From Hydraulic, Mechanical, And Well-Performance Problems.
Frequently Asked Questions
Why Is My Submersible Pump Pulling Too Many Amps?
The Pump May Be Experiencing Low Voltage, Excessive Flow, Mechanical Drag, Sand Blockage, Incorrect Wiring, Phase Imbalance, Motor-Winding Damage, Or A Defective Starting Circuit.
Can Low Voltage Cause High Amps?
Yes. Low Voltage Can Increase Motor Current And Winding Temperature When The Motor Attempts To Produce The Required Torque. Always Measure Voltage While The Pump Is Running.
Can High Water Flow Cause High Motor Current?
Yes. Many Centrifugal Deep Well Pumps Require More Power As Flow Increases. Confirm The Actual Relationship Using The Specific Pump Curve.
Why Does My Well Pump Trip The Overload After Several Minutes?
Possible Causes Include Sustained Overcurrent, Falling Voltage, Insufficient Motor Cooling, High Water Temperature, Mechanical Friction, Incorrect Overload Settings, Or Frequent Starting.
Why Are The Amps High But Water Pressure Is Low?
High Current With Low Pressure May Indicate A Blocked Or Worn Pump, Sand Damage, Mechanical Drag, A Pipe Leak, Incorrect Rotation, Or A Mismatched Pump And Motor.
Can A Bad Capacitor Cause High Amps?
Yes. A Failed Start Or Run Capacitor Can Prevent A Single-Phase Motor From Accelerating Correctly, Producing High Current, Humming, And Overload Trips.
Can Sand Make A Submersible Pump Draw More Current?
Yes. Sand Can Increase Friction, Block Impeller Passages, Damage Bearings, And Restrict Rotation. The Pump May Draw High Current While Producing Less Water.
Should Running Amps Be Below Nameplate Amps?
Running Current Should Remain Within The Range Permitted By The Motor Manufacturer. Do Not Assume That Continuous Operation Above Full-Load Current Is Acceptable Because A Service-Factor Value Appears On The Nameplate.
Can A VFD Reduce High Pump Current?
A Correctly Selected And Programmed VFD Can Limit Speed And Control Flow, But It Cannot Repair A Damaged Motor, Blocked Pump, Incorrect Wiring, Or Undersized Cable.
Is It Safe To Keep Running A Pump With High Amps?
No. Continued Operation Can Overheat The Motor, Damage Insulation, Burn Connections, And Cause Complete Pump Failure. Stop The Pump And Identify The Cause If Current Exceeds The Manufacturer’s Permitted Limit.
Final Answer
When Submersible Pump Amps Are Too High, Begin By Comparing The Running Current With The Motor Nameplate. Then Measure Loaded Voltage, Phase Imbalance, Water Flow, Discharge Pressure, Total Dynamic Head, Winding Resistance, And Insulation Resistance.
Do Not Increase The Overload Setting To Hide The Problem. Correct The Electrical, Hydraulic, Or Mechanical Cause Before Returning The Pump To Continuous Operation.
For A New Or Replacement Submersible Pump, Send Liyuan Pump Your Required Flow, Total Dynamic Head, Well Diameter, Pump Setting Depth, Voltage, Frequency, Water Quality, And Operating Conditions. This Allows The Pump And Motor To Be Matched For Reliable Current, Efficient Operation, And Long Service Life.
Email:Liyuan@liyuan-pump.com
WhatsApp:+86 181-2828-2767