IEC Manual Motor Starter Protectors Frequently Asked Questions
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Question:
What are Auxiliary Contacts used for?
Answer
This is an added accessory for controlling circuits or signaling a PLC of Manual Motor Starter /Protector condition.
FAQ ID: 355
Question:
Is the phase loss protection electronic?
Answer
No - The phase loss trip is electromechanical and trips when one of the three thermal strips carries a different current than the others.
FAQ ID: 357
Question:
What is the purpose of the Shunt Trip?
Answer
This is an accessory that is added to the Manual Motor Starter Protector for remote tripping of the Manual Motor Starter Protector by applying a voltage to its coil.
FAQ ID: 359
Question:
What is an Undervoltage Trip accessory used for?
Answer
This accessory is used in a manual motor application to automatically trip the Manual Motor Starter Protector in an undervoltage condition.
FAQ ID: 360
Question:
Is it necessary to install a shunt trip or undervoltage trip in the Manual Motor Starter/ Protector?
Answer
Not necessarily - Only if you need this protection or option.
FAQ ID: 361
Question:
What is the overload trip curve for the Manual Motor Starter/ Protector?
Answer
It is a Class 10 type trip curve device.
FAQ ID: 362
Question:
What is the short circuit trip rating for the Manual Motor Starter / Protector?
Answer
MSP's Short circuit breaking capacity up to 690 Volt is 100 kA per IEC 947--2 EN 60947-2 for the MS25-16 and MS25-25; others require backup fuses, slow blow type fuse.
See more details in our application notes section
FAQ ID: 363
Question:
Can I use the Manual Motor Starter/ Protector on a single phase motor?
Answer
Yes, but the motor circuit current must pass through all three MSP circuits. These wiring diagrams are printed on the inside of the product box.
FAQ ID: 364
Question:
Can the Manual Motor Starter /Protector be used alone or only with a contactor?
Answer
The Manual Motor Starter/ Protector can be used alone in a manual motor control application. The motor would then be controlled by the ON/OFF pushbuttons on the front of the Manual Starter Protector. However, we do not offer a dedicated enclosure for Manual MSP operation at this time.
FAQ ID: 365
Question:
What agency approvals do the MS25 series devices have?
Answer
CUL,CE & UL508 B,C, & D motor type compliant.
This product is listed as a "Manual motor controller/potector" see UL file# E195426. The MS25 is NOT a Type E "Self-Protected Combination Motor Controller".
FAQ ID: 366
Question:
What is the impact resistance of the Manual Motor Starter/ Protectors at 20 ms duration?
Answer
20g
FAQ ID: 367
Question:
What is the ambient temperature of the Manual Motor Starter/ Protectors?
Answer
-25c to 50c (open) -25c to 40c (enclosed)
FAQ ID: 368
Question:
What are the climate classifications of the Manual Motor Starter/ Protectors?
Answer
IEC 68-2-3, IEC 68-2-30
FAQ ID: 369
Question:
What is the protection degree of the Manual Motor Starter/ Protector?
Answer
IP 20
FAQ ID: 370
Question:
Are the Manual Motor Starter/ Protectors Din Rail mountable?
Answer
Yes, you can mount individually or use an adapter. The adapter allows the mounting of two Din Rail devices on a single Din Rail.
FAQ ID: 371
Question:
Does the shunt trip have auto reset capabilities?
Answer
No, This will have to be reset manually.
FAQ ID: 374
Question:
How does the Manual Motor Starter/Protector & the Contactor transfer current from one to the other?
Answer
The current is transferred through wiring supplied by the customer.
FAQ ID: 375
Question:
Do you have a AWG to Metric conversion chart?
Answer
You will find that info at the following link: http://support.automationdirect.com/notes/awg.html
FAQ ID: 415
Question:
I am trying to use a starter for a 3hp motor on a 120 vac 15 amp circuit. It keeps tripping out. What is going on?
Answer
OK, 1 hp is equal to 746 watts. Given all of the other circumstances of heat loss, power factor inefficiency, it is safe to say that a 1 hp motor requires more like 1000 watts. A 120 vac 15 amp circuit can on give a max of 1800 watts. If we do the math, we can see that the power requirements out weigh the ability of the circuit to run anything over 1.5 hp.
My 3 hp saw works on the same circuit? It is not the conventional hp rating that is given to your saw. It is the near stall measurement, if you were to keep it in that condition that the manufacturer measured it at, the saw would melt.
FAQ ID: 837
Question:
What are the sizing guidelines for starters and contactors?
Answer
Article 430 of NEC.
FAQ ID: 838
Question:
I need to start and stop a motor; I am confused on what the difference between an MSP, starter, and contactor are?
Answer
The contactor is the basic denominator in this equation. It is nothing more than an electric switch or relay. When one uses overload relays (heaters) or an MSP (motor starter protector) in conjunction with a contactor, it becomes a starter.
The conventional method is a contactor on top and an overload unit below.
The alternative method is to have the manual starter (MSP) on top as the overload, with the contactor on the bottom. The MSP is always closed and will perform the same duty as the conventional overload unit previously mentioned.
The MSP by itself acts as a manual motor starter. Starting the motor without the aid of an electric control coil or relay; simply by depressing the local start push-button.
FAQ ID: 840
Question:
What are the coordination levels used to classify starters and protectors?
Answer
The coordination levels are as follows:
Type 1
o No danger to personnel
o No danger to equipment other than relay itself
o Relay must be serviced or replaced
Type 2
o No danger to personnel
o No danger to other equipment
o No danger to relay other than minor welding of contacts
o Relay can be used without service or repair
FAQ ID: 856
Question:
What are the differences between the uses of MSPs in USA versus their uses internationally?
Answer
„h MSP¡¦s USA
o Does not meet UL 489
o Cannot be used for stand alone short circuit breaking
o Can be used as ¡§group motor rating¡¨ (UL/CSA)
o NEC 430-53 (sizing guidelines)
o Indicates that a single short circuit protective device can protect several branch circuits.
o If the short circuit current exceeds the withstand rating of the MSP then fuses must be used in series to protect the circuit or the system must be redesigned to accommodate (NEC 110-10).
„h MSP¡¦s international
o IEC 947-4-1
o Recognized as a stand-alone short circuit protecting device.
o Back-up fuses are only required when the fault current exceeds breaking capacity of the MSP.
FAQ ID: 857
Question:
What are the NEC references for a motor circuit?
Answer
Disconnection
o NEC part j
Short circuit protection
o NEC part d
Controller
o NEC part g
Overload protection
o NEC part c
Motor
o NEC part a
FAQ ID: 858
Question:
NEMA or IEC style starters and protectors?
Answer
NEMA
NEMA has higher withstand ratings typically
o NEMA has a standard sizing scheme that provides for interchangeability from the different manufacturers.
o Designed with reserve capability.
o Molded coils
IEC
o IEC has no standard sizing guidelines and rating selection is evaluated into utilization categories.
o Tape wound open coils.
Both types have the same trip classes 10, 20, 30.
FAQ ID: 859
Question:
What is a trip class?
Answer
A trip class is the amount of time in seconds measured for meltdown of heater element with 6 times the FLA applied.
FAQ ID: 860
Question:
What is the withstand rating?
Answer
The withstand rating is the maximum amount of current that an enclosure can safely contain.
FAQ ID: 861
Question:
What is breaking capacity/interrupting rating?
Answer
The breaking capacity/interrupting rating is the maximum amount of current that a protection device can safely open or clear.
FAQ ID: 862
Question:
What is fault current?
Answer
Fault current is the maximum amount of current available for a short circuit condition in certain point of the power distribution system.
FAQ ID: 863
Question:
What is an Overload condition?
Answer
An overload is the over current condition that exceeds the normal full load current (FLA) of the motor (can be 6-10 times the FLA.)
FAQ ID: 864
Question:
What is a short circuit fault?
Answer
A short-circuit fault in a power system is an abnormal condition that involves one or more phases unintentionally coming in contact with ground or each other. Thus, short-circuit protection is necessary to protect personnel and apparatus from the destructive effects of the resulting excessive current flow, which is caused by the relatively low impedance of the short-circuit fault connection.
FAQ ID: 865
Question:
What is the minimum cycle time for a starter?
Answer
When the power is stopped to the motor, the field starts to collapse. Remember this takes a certain amount of time. For that very brief moment; there is some CEMF at the motor terminals. Even though it is decaying just like a standard inductive circuit.
Here’s the problem of two short of cycle time. When power is re-applied, the incoming power can actually be out of phase with the collapsing field. The in-rush current can be at twice the LRA (600% FLA on start-up, up to 1200% in this worse case scenario.)
Of course the above example is a worse case scenario, the stress on the windings and the mechanical stresses that can occur out way the benefits of cycling too fast.
You should find out how long the time constant lasts for the particular motor in your project and give it at least 6-10 times the amount.
Refer to NEMA MG-1 defines the open circuit AC time constant.
FAQ ID: 889
Question:
Do you sell covers for the MSP25 series motor starter protectors?
Answer
We do not sell MSP enclosures.
FAQ ID: 897
Question:
Can I use a motor starter protector with Variable speed drives and inverters?
Answer
They are only recommended for multiple motor applications from the output of a single drive. The drive handles the aggregate current monitoring, not the individual motor branch current.
NEC article 430 53c “group motor rating” deals with the concept of conventional across the line motor starters and the requirements of short-circuit protection from feeder to motor branch circuit. These guidelines do not mention variable speed drives. The recommendation is always to follow the manufacturer specification. In this case Hitachi recommends J class fuses.
You would never use a MSP, because it is not rated as a SSPD (short circuit protective device) in North America, in place of these J class fuses. There is also no need of an overload on the output side of the drive unless there are multiple motors being used.
Always check with your local inspectors and municipalities before an installation to verify their local requirements which may differ from the National Code.
FAQ ID: 898
Question:
Can the starters be used for dc motors?
Answer
All of our starters and contactors have an IEC utilization code of AC-1 (non-inductive or slightly inductive loads) and AC-3 (inductive loads like induction motors.)
Under IEC 60947-2, -3, -4, and 5. The Categories for dc rated low voltage switchgear and control gear are clearly defined.
The reasons for not using an AC rated contactor in a dc system:
1.) Not specified by the manufacturer.
2.) The device does not monitor the dc voltage the same way.
3.) The make or break ratings are higher in dc applications.
4.) No arc suppression.
FAQ ID: 925
Question:
Does Automationdirect.com sell a Manual Motor Starter Protector that is Type E?
Answer
Yes we do. The Fuji MMS (Manual Motor Starters) are UL 508 and listed as Self-Protected Combination Motor Controller. They are also Suitable for Group Motor Installation and Suitable as Motor Disconnect.
FAQ ID: 1031